[EXECUTION COPY]





                                  $150,000,000


                                CREDIT AGREEMENT


                                   dated as of


                                  June 28, 1996



                                      among


                          AMSC Subsidiary Corporation,


                     American Mobile Satellite Corporation,


                            The Banks Listed Herein,


                   Morgan Guaranty Trust Company of New York,
                             as Documentation Agent,


                                       and


                         Toronto Dominion (Texas), Inc.,
                             as Administrative Agent



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                                TABLE OF CONTENTS



                                                                            Page


                                    ARTICLE 1

                                   DEFINITIONS

SECTION 1.1.   Definitions.................................................... 1
SECTION 1.2.   Accounting Terms and Determinations........................... 25


                                    ARTICLE 2

                                   THE CREDITS

SECTION 2.1.   Commitments to Lend........................................... 26
SECTION 2.2.   Method of Borrowing........................................... 26
SECTION 2.3.   Notes......................................................... 28
SECTION 2.4.   Maturity of Loans; Mandatory Prepayments...................... 28
SECTION 2.5.   Interest Rates................................................ 30
SECTION 2.6.   Commitment Fees............................................... 32
SECTION 2.7.   Optional Termination or Reduction of Commitments.............. 32
SECTION 2.8.   Method of Electing Interest Rates............................. 32
SECTION 2.9.   Mandatory Termination and Reduction of Commitments............ 34
SECTION 2.10.  Optional Prepayments.......................................... 34
SECTION 2.11.  General Provisions as to Payments............................. 35
SECTION 2.12.  Funding Losses................................................ 36
SECTION 2.13.  Computation of Interest and Fees.............................. 36


                                    ARTICLE 3

                                   CONDITIONS

SECTION 3.1.   Closing....................................................... 36
SECTION 3.2.   Initial Borrowing............................................. 40
SECTION 3.3.   All Borrowings................................................ 41


                                    ARTICLE 4

                         REPRESENTATIONS AND WARRANTIES

SECTION 4.1.   Corporate Existence and Power................................. 42
SECTION 4.2.   Corporate Authorization; No Contravention..................... 42
SECTION 4.3.   Government Approvals.......................................... 43
SECTION 4.4.   Binding Effect.................................................43
SECTION 4.5.   Litigation.................................................... 44
SECTION 4.6.   No Default.................................................... 44

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SECTION 4.7.   ERISA Compliance.............................................. 44
SECTION 4.8.   Title to Property............................................. 46
SECTION 4.9.   Taxes......................................................... 46
SECTION 4.10.  Financial Condition........................................... 46
SECTION 4.11.  Environmental Matters......................................... 47
SECTION 4.12.  Regulated Entities............................................ 47
SECTION 4.13.  Subsidiaries.................................................. 47
SECTION 4.14.  Insurance..................................................... 48
SECTION 4.15.  Project Compliance............................................ 48
SECTION 4.16.  Business...................................................... 48
SECTION 4.17.  Collateral; Property.......................................... 48
SECTION 4.18.  Common Collateral............................................. 48
SECTION 4.19.  Sufficiency of Project Documents.............................. 49
SECTION 4.20.  Disclosure.................................................... 49
SECTION 4.21.  Effectiveness of Project Documents............................ 50


                                    ARTICLE 5

                                    COVENANTS

SECTION 5.1.   Information................................................... 50
SECTION 5.2.   Certificates; Other Information............................... 51
SECTION 5.3.   Notices....................................................... 52
SECTION 5.4.   Conduct of Business; Preservation of Corporate Existence...... 54
SECTION 5.5.   Maintenance of Property....................................... 55
SECTION 5.6.   Maintenance of Insurance...................................... 55
SECTION 5.7.   Payment of Obligations........................................ 58
SECTION 5.8.   Compliance with Laws.......................................... 59
SECTION 5.9.   Inspection of Property and Books and Records.................. 59
SECTION 5.10.  Environmental Laws............................................ 60
SECTION 5.11.  Use of Proceeds............................................... 60
SECTION 5.12.  Common Collateral Documents and Guaranties.................... 60
SECTION 5.13.  No Subsidiaries............................................... 61
SECTION 5.14.  FCC Approval.................................................. 61
SECTION 5.15.  Government Approvals.......................................... 62
SECTION 5.16.  Further Assurances............................................ 62
SECTION 5.17.  Limitation on Liens........................................... 63
SECTION 5.18.  Disposition of Assets, Consolidations and Mergers............. 64
SECTION 5.19.  Principal Subsidiary Guaranties............................... 66
SECTION 5.20.  Employee Contracts and Arrangements........................... 66
SECTION 5.21.  Loans and Investments......................................... 66
SECTION 5.22.  Limitation on Indebtedness.................................... 67
SECTION 5.23.  Transactions with Affiliates.................................. 68
SECTION 5.24.  Compliance with ERISA......................................... 69
SECTION 5.25.  Project Documents............................................. 69
SECTION 5.26.  Lease Obligations............................................. 69
SECTION 5.27.  Restricted Payments........................................... 70
SECTION 5.28.  Leverage Ratio................................................ 70
SECTION 5.29.  Balance Sheet Leverage Ratio.................................. 71

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SECTION 5.30.  Indebtedness Per Subscriber................................... 71
SECTION 5.31.  Minimum Performance........................................... 71
SECTION 5.32.  Interest Coverage............................................. 72
SECTION 5.33.  Capital Expenditures.......................................... 72
SECTION 5.34.  Change in Structure........................................... 72
SECTION 5.35.  Accounting Changes............................................ 73
SECTION 5.36.  Rate Contracts................................................ 73


                                    ARTICLE 6

                                    DEFAULTS

SECTION 6.1.   Events of Default............................................. 73
SECTION 6.2.   Notice of Default............................................. 78


                                    ARTICLE 7

                                   THE AGENTS

SECTION 7.1.   Appointment and Authorization................................. 78
SECTION 7.2.   Agents and Affiliates......................................... 79
SECTION 7.3.   Action by Agents.............................................. 79
SECTION 7.4.   Consultation with Experts..................................... 79
SECTION 7.5.   Liability of Agents........................................... 79
SECTION 7.6.   Indemnification............................................... 80
SECTION 7.7.   Credit Decision............................................... 80
SECTION 7.8.   Successor Agent............................................... 80
SECTION 7.9.   Agents' Fees.................................................. 80


                                    ARTICLE 8

                             CHANGE IN CIRCUMSTANCES

SECTION 8.1.   Basis for Determining Interest Rate Inadequate or Unfair...... 81
SECTION 8.2.   Illegality.................................................... 81
SECTION 8.3.   Increased Cost and Reduced Return............................. 82
SECTION 8.4.   Taxes......................................................... 84
SECTION 8.5.   Base Rate Loans Substituted for Affected Euro-Dollar Loans.... 86


                                    ARTICLE 9

                                 PARENT GUARANTY

SECTION 9.1.   The Parent Guaranty........................................... 87
SECTION 9.2.   Guaranty Unconditional........................................ 87

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                                                                            Page

SECTION 9.3.   Discharge Only Upon Payment In Full; Reinstatement In
               Certain Circumstances......................................... 88
SECTION 9.4.   Waiver by the Parent Guarantor................................ 88
SECTION 9.5.   Subrogation................................................... 88
SECTION 9.6.   Stay of Acceleration.......................................... 89


                                   ARTICLE 10

                                  MISCELLANEOUS

SECTION 10.1.   Notices...................................................... 89
SECTION 10.2.   No Waivers................................................... 89
SECTION 10.3.   Expenses; Indemnification.................................... 89
SECTION 10.4.   Sharing of Set-Offs.......................................... 90
SECTION 10.5.   Amendments and Waivers....................................... 91
SECTION 10.6.   Successors and Assigns....................................... 91
SECTION 10.7.   Collateral................................................... 93
SECTION 10.8.   Governing Law; Submission to Jurisdiction.................... 93
SECTION 10.9.   Counterparts; Integration; Effectiveness..................... 94
SECTION 10.10.  WAIVER OF JURY TRIAL......................................... 94
SECTION 10.11.  Confidentiality.............................................. 94



 PRICING SCHEDULES
 RELEASE DATE SCHEDULE
  SCHEDULE I   - Common Collateral Documents
  SCHEDULE II  - Project Documents


                             EXHIBIT A - Note
                 EXHIBIT B - Opinions of Counsel and Special FCC
                Counsel      for the Parent Guarantor and the Borrower EXHIBIT C
                             - Opinion of Special Counsel for the Agents EXHIBIT
                             D - Assignment and Assumption Agreement EXHIBIT E -
                             Notice of New  Secured  Party and Notice of Secured
                             Amount EXHIBIT F - Principal Subsidiary Guaranty

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                                CREDIT AGREEMENT


                  AGREEMENT  dated as of June 28,  1996  among  AMSC  SUBSIDIARY
CORPORATION,  AMERICAN  MOBILE  SATELLITE  CORPORATION,  the BANKS listed on the
signature  pages  hereof,   MORGAN  GUARANTY  TRUST  COMPANY  OF  NEW  YORK,  as
Documentation Agent and TORONTO DOMINION (TEXAS), INC., as Administrative Agent.

                  The parties hereto agree as follows:


                                    ARTICLE 1


                                   DEFINITIONS

                  SECTION 0.1.  Definitions.  The following terms, as used
herein, have the following meanings:

                  "Adjusted London Interbank Offered Rate" has the meaning set
forth in Section 2.5(b).

                  "Administrative Agent" means Toronto Dominion (Texas), Inc.
in its capacity as administrative agent for the Banks hereunder, and its
successors in such capacity.

                  "Administrative  Questionnaire"  means,  with  respect to each
Bank, an administrative questionnaire in the form prepared by the Administrative
Agent and  submitted to the  Administrative  Agent (with a copy to the Borrower)
duly completed by such Bank.

                  "Affiliate"  means, as to any Person,  any other Person which,
directly or  indirectly,  is in control of, is controlled by, or is under common
control with, such Person. A Person shall be deemed to control another Person if
the controlling Person possesses, directly or indirectly, the power to direct or
cause the direction of the management and policies of the other Person,  whether
through the ownership of voting  securities,  by contract or otherwise.  Without
limitation,  any director,  executive officer or beneficial owner of 30% or more
of the equity of a Person shall,  for the purposes of this Agreement,  be deemed
to control the other Person.

                  "Agents" means the Administrative  Agent and the Documentation
Agent, and "Agent" means either of the foregoing.

                  "Applicable  Lending Office" means,  with respect to any Bank,
(i) in the case of its Base Rate Loans,  its Domestic Lending Office and (ii) in
the case of its Euro-Dollar Loans, its Euro-Dollar Lending Office.

                  "Asset  Sale"  means  any  sale,  lease or  other  disposition
(including any such transaction  effected by way of merger or  consolidation) by
the Parent Guarantor or any of its Subsidiaries of any asset, including without

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limitation any  sale-leaseback  transaction,  whether or not involving a capital
lease, but excluding (i)  dispositions of inventory,  cash, cash equivalents and
other cash management investments and obsolete,  unused or unnecessary equipment
and  undeveloped  real estate,  in each case in the ordinary course of business,
(ii)  dispositions  to the  Borrower or a  Subsidiary  of the Borrower and (iii)
Permitted Dispositions.

                  "Assignee" has the meaning set forth in Section 10.6(c).

                  "Availability  Period" means the period from and including the
Closing  Date to and  including  December  31,  1996  or,  if such  day is not a
Euro-Dollar Business Day, the next preceding Euro-Dollar Business Day.

                  "Bank" means each bank listed on the  signature  pages hereof,
each  Assignee  which  becomes a Bank  pursuant  to Section  10.6(c),  and their
respective successors.

                  "Baron Capital" means Baron Capital Partners, L.P., a
Delaware limited partnership.

                  "Baron Capital Guaranty" means the Guaranty,  dated as of June
28, 1996, made by Baron Capital to the Administrative  Agent for its own benefit
and the  benefit  of the  Banks  and the  banks  party to the  Revolving  Credit
Agreement, as the same may be amended from time to time.

                  "Baron  Capital  Letter of Credit"  means the Letter of Credit
dated  June 28,  1996  issued by The Bank of New York for the  account  of Baron
Capital for the benefit of the Administrative Agent on behalf of the Banks.

                  "Base Rate" means,  for any day, a rate per annum equal to the
higher of (i) the Prime Rate for such day and (ii) the sum of 5/8 of 1% plus the
Federal Funds Rate for such day.

                  "Base Rate Loan" means (i) a Loan which bears  interest at the
Base Rate pursuant to the  applicable  Notice of Borrowing or Notice of Interest
Rate Election or the provisions of Article 8 or (ii) an overdue amount which was
a Base Rate Loan immediately before it became overdue.

                  "Base  Rate  Margin"  means a rate  per  annum  determined  in
accordance with the Pricing Schedule.

                  "Borrower"  means  AMSC  Subsidiary  Corporation,  a  Delaware
corporation dually  incorporated as a Virginia Public Service  Corporation,  and
its successors.

                  "Borrowing" means a borrowing hereunder consisting of Loans
made to the Borrower on the same day pursuant to Article 2, all of which
Loans are of the same type (subject to Article 8) and, except in the case of

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Base Rate Loans, have the same initial Interest Period. A Borrowing is a
"Base  Rate  Borrowing"  if such  Loans  are Base Rate  Loans or a  "Euro-Dollar
Borrowing" if such Loans are Euro-Dollar Loans.

                  "Bridge  Agreement"  means the Securities  Purchase  Agreement
dated as of January 19, 1996,  as amended by Amendment No. 1 thereto dated as of
April 19, 1996, by and among the Borrower, the Parent Guarantor, Morgan Guaranty
Trust  Company  of New York,  Toronto  Dominion  Investments,  Inc.,  and Hughes
Communications  Satellite  Services,  Inc., and as further  amended from time to
time.

                  "Bridge Notes" means the "Notes" as defined in the Bridge
Agreement.

                  "Capital Lease Obligations" means all monetary  obligations of
a Person under any leasing or similar  arrangement  which,  in  accordance  with
GAAP, is classified as a capital lease.

                  "Cash Equivalents" means:

                  (a)  securities  issued or fully  guaranteed or insured by the
United States  Government or any agency thereof and backed by the full faith and
credit of the United  States  having  maturities  of not more than twelve months
from the date of acquisition;

                  (b)  certificates of deposit,  time deposits,  Eurodollar time
deposits,  or bankers'  acceptances having in each case a tenor of not more than
six months,  issued by any Bank, or by any U.S.  commercial bank having combined
capital and surplus of not less than  $500,000,000  whose short term  securities
are rated both A-1 or higher by Standard & Poor's  Corporation and P-1 or higher
by Moody's Investors Services, Inc.;

                  (c)  commercial paper of an issuer rated either at least A-1
by Standard & Poor's Ratings Group, a division of McGraw-Hill, Inc.
and/or P-1 by Moody's Investors Service Inc. and in either case having a
tenor of not more than three months;

                  (d)  repurchase agreements fully collateralized by
securities issued by United States Government agencies; and

                  (e) money  market  mutual  funds  invested in the  instruments
permitted by clauses (a), (b), (c) and (d) above.

                  "CERCLA" has the meaning specified in the definition
"Environmental Laws".

                  "CGS"  means  the  communications   ground  segment  designed,
developed  and  manufactured  for the  Borrower  pursuant  to the  Contract  for
Communications  Ground Segment (Contract Number  AMSC-CGS-001)  between Borrower
and Westinghouse Electric Corporation dated as of May 1, 1992,
as amended.

                  "Change In  Control"  means (i) any person or group of persons
(within the meaning of Section 13 or 14 of the Securities Exchange Act of

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1934, as amended) shall have  beneficial  ownership  (within the meaning of Rule
13d-3  promulgated by the Securities and Exchange  Commission under said Act) of
more  shares of the  outstanding  capital  stock of the  Parent  Guarantor  than
Hughes,  (ii) Hughes  shall have  beneficial  ownership  of less than 25% of the
outstanding  capital stock of the Parent Guarantor,  (iii) Hughes shall cease to
have  beneficial  ownership of shares of capital stock of the Parent  Guarantor,
(iv) during any period of 24 consecutive  calendar months,  individuals who were
directors of the Parent Guarantor on the first day of such period shall cease to
constitute  a  majority  of the  board  of  directors  of the  Parent  Guarantor
(ignoring for this purpose replacements of  stockholder-designated  directors by
successor   directors   designated   by  the  same   stockholder   or  group  of
stockholders),  or (v)  the  Parent  Guarantor  shall  cease  to own  all of the
outstanding capital stock of the Borrower.

                  "Closing  Date" means the date on or after the Effective  Date
on which the Documentation  Agent shall have received the documents specified in
or pursuant to Section 3.1(a).

                  "Code" means the Internal Revenue Code of 1986, as amended,
or any successor statute.

                  "Commitment"  means, with respect to each Bank, the amount set
forth  opposite the name of such Bank on the  signature  pages  hereof,  as such
amount may be reduced from time to time pursuant to Section 2.7.

                  "Common  Collateral"  means all property as to which Liens are
granted  from time to time to the  Common  Collateral  Agent  under  the  Common
Collateral Documents.

                  "Common Collateral Agent" means Bank of America National Trust
and Savings  Association,  in its  capacity as  collateral  agent for the Common
Collateral  Parties  under  the  Intercreditor   Agreement,  and  any  successor
collateral agent thereunder.

                  "Common  Collateral  Documents" means,  collectively,  (i) the
Security  Agreement  and the Parent  Pledge  Agreement  described  on Schedule I
hereto,  the Intercreditor  Agreement,  all intercreditor  agreements,  security
agreements,  mortgages, deeds of trust, pledge agreements,  patent and trademark
assignments,  lease  assignments,  guarantees and other similar agreements among
the Parent Guarantor, the Borrower, their respective Subsidiaries and the Common
Collateral  Agent for the  benefit of the  Common  Collateral  Parties,  and all
financing  statements  (or  comparable  documents)  now or  hereafter  filed  in
connection  therewith,  (ii) the Notice of Amount of Secured Obligations and the
Notice of New Secured Party and (iii) the Security  Agreement  Amendment and any
other amendments,  supplements,  modifications,  substitutions and extensions of
any of the  foregoing,  in each case in form and substance  satisfactory  to the
Documentation Agent and the Common Collateral Agent.

                  "Common Collateral Parties" means the "Secured Parties" as
defined in the Intercreditor Agreement.


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                  "Competitor of the Borrower" means any Person who (i) has made
application  to the FCC to provide  services which are similar to those provided
by the  Borrower  (the  "Services")  or to  obtain a  license  with  respect  to
bandwidth  used by the Borrower or for which the  Borrower has made  application
and who, in the reasonable opinion of the Borrower,  competes, or would, if such
application  were approved,  compete with the Borrower to provide Services or to
obtain such  bandwidth,  or (ii)  becomes  engaged in the  business of providing
Services,  or  producing,  or  providing  vendor  financing  with  respect to, a
significant  component of a communications  system that provides or will provide
services which are similar to the Services.

                  "Consolidated Capital Expenditures" means, for any period, the
additions to property,  plant and  equipment of the Parent  Guarantor  Group for
such period, as determined in accordance with GAAP.

                  "Consolidated  Cash Interest  Expense"  means,  for any fiscal
period,  the aggregate amount of interest accrued or paid (without  duplication)
by the Parent  Guarantor Group during such period,  determined on a consolidated
basis,  including,  without limitation,  (i) any interest accrued or paid during
such period which is  capitalized in accordance  with GAAP,  (ii) the portion of
any obligation  under capital leases  allocable to interest  expense during such
period in accordance  with GAAP, and (iii) the portion of any debt discount that
shall be amortized in such period,  minus such of the foregoing items as are not
payable in cash during such period or within one year  following the last day of
such period.

                  "Consolidated   Current   Assets"   means   at  any  date  the
consolidated  current assets of the Parent Guarantor Group determined as of such
date.

                  "Consolidated  Current  Liabilities" means at any date (i) the
consolidated  current  liabilities of the Parent  Guarantor  Group plus (ii) the
Contingent Obligations of the Parent Guarantor Group with respect to the current
liabilities of any Person (other than any member of the Parent Guarantor Group),
all determined as of such date.

                  "Consolidated  Interest  Expense" means,  for any period,  the
interest  expense of the Parent  Guarantor  Group  determined on a  consolidated
basis for such period.

                  "Consolidated  Net  Working  Investment"  means  at  any  date
Consolidated  Current  Assets  (exclusive  of cash and cash  equivalents)  minus
Consolidated Current Liabilities (exclusive of Indebtedness).

                  "Consolidated  Subsidiary"  means at any date and with respect
to any Person,  any  Subsidiary  or other  entity the accounts of which would be
consolidated with those of such Person in its consolidated  financial statements
if such statements were prepared as of such date.

                  "Consolidated Tangible Net Worth" means at any date the
consolidated stockholders' equity of the Parent Guarantor Group less its

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consolidated  Intangible Assets, all determined as of such date. For purposes of
this definition "Intangible Assets" means the amount (to the extent reflected in
determining such consolidated  stockholders' equity) of (i) all write-ups (other
than write-ups  resulting from foreign  currency  translations  and write-ups of
assets  of a  going  concern  business  made  within  twelve  months  after  the
acquisition of such business)  subsequent to December 31, 1995 in the book value
of any asset  owned by the  Parent  Guarantor  Group,  (ii) all  Investments  in
unconsolidated  Subsidiaries and all equity investments in Persons which are not
Subsidiaries  and (iii) all unamortized  debt discount and expense,  unamortized
deferred charges,  goodwill,  patents,  trademarks,  service marks, trade names,
anticipated future benefit of tax loss carry-forwards,  copyrights, organization
or developmental expenses and other intangible assets.

                  "Contingent  Obligation"  means, as applied to any Person, any
direct or indirect  liability of that Person with  respect to any  Indebtedness,
lease,   dividend,   letter  of  credit  or  other   obligation   (the  "primary
obligations")  of another  Person (the "primary  obligor"),  including,  without
limitation,  any obligation of that Person,  whether or not  contingent,  (a) to
purchase,  repurchase  or  otherwise  acquire such  primary  obligations  or any
property constituting direct or indirect security therefor, or (b) to advance or
provide  funds (i) for the payment or discharge of any such primary  obligation,
or (ii) to maintain  working capital or equity capital of the primary obligor or
otherwise to maintain the net worth or solvency or any balance sheet item, level
of income or  financial  condition  of the primary  obligor,  or (c) to purchase
property, securities or services primarily for the purpose of assuring the owner
of any such  primary  obligation  of the ability of the primary  obligor to make
payment of such primary obligation,  or (d) otherwise to assure or hold harmless
the holder of any such primary  obligation  against loss in respect thereof,  or
(e) to purchase or otherwise acquire,  or otherwise to assure a creditor against
loss in respect of any Indebtedness. For purposes of this definition, the amount
of any  Contingent  Obligation  shall be  deemed  to be an  amount  equal to the
maximum reasonably anticipated liability in respect thereof.

                  "Contractual   Obligation"   means,  as  to  any  Person,  any
provision  of  any  security   issued  by  such  Person  or  of  any  agreement,
undertaking,  contract, indenture,  mortgage, deed of trust or other instrument,
document or  agreement  to which such Person is a party or by which it or any of
its property is bound.

                  "Controlled  Group" means the Parent  Guarantor,  the Borrower
and all Persons (whether or not incorporated) under common control or treated as
a single  employer  with the  Parent  Guarantor,  the  Borrower  or any of their
respective Subsidiaries pursuant to Section 414(b), (c), (m) or (o) of the Code.

                  "Default"  means any condition or event which  constitutes  an
Event of  Default  or which  with the  giving of notice or lapse of time or both
would, unless cured or waived, become an Event of Default.


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                  "Disclosure  Schedule"  means the Disclosure  Schedule of even
date herewith attached hereto and hereby made part of this Agreement.

                  "Documentation  Agent" means Morgan  Guaranty Trust Company of
New York in its capacity as documentation agent for the Banks hereunder, and its
successors in such capacity.

                  "dollars" means United States dollars.

                  "Domestic  Business  Day"  means  any day  except a  Saturday,
Sunday or other day on which commercial banks in New York City are authorized by
law to close.

                  "Domestic  Lending  Office" means, as to each Bank, its office
located  at its  address  set  forth  in its  Administrative  Questionnaire  (or
identified in its  Administrative  Questionnaire as its Domestic Lending Office)
or such  other  office  as such Bank may  hereafter  designate  as its  Domestic
Lending Office by notice to the Borrower and the Administrative Agent.

                  "EBITDA" means, for any period, for the Parent Guarantor Group
on a consolidated basis,  determined in accordance with GAAP, the sum of (i) the
net  income  (or net  loss)  plus  (ii) all  amounts  treated  as  expenses  for
depreciation and interest and the amortization of intangibles of any kind to the
extent included in the  determination  of such net income (or loss),  plus (iii)
all taxes on or  measured  by gross or net income to the extent  included in the
determination  of such net income  (or loss).  For  purposes  of the  foregoing,
notwithstanding  any  requirement  of GAAP to the  contrary,  "net income" shall
exclude:

                  (a) any  restoration  to  income of any  contingency  reserve,
except to the extent  that  provision  for such  reserve  was made out of income
accrued  during such period and except for normal  accruals and reversals in the
ordinary course of business;

                  (b) any write-up or  write-down  of any asset,  and all equity
accounting  adjustments for consolidated or unconsolidated  investments in Joint
Ventures, Subsidiaries, and other business organizations;

                  (c)  any net gain from the collection of the proceeds of
life insurance policies;

                  (d) any  gain or loss  arising  from  the  acquisition  of any
securities or  Indebtedness  and any net loss arising from the exercise or grant
of any warrant or option;

                  (e)  any deferred credit representing the excess of equity
in any Person at the date of acquisition over the cost of the investment
in such Person;

                  (f) any  aggregate  net  gain (or  loss)  during  such  period
arising from the sale,  exchange or other  disposition  of capital  assets (such
term to include all fixed assets, whether tangible or intangible,

                                        7





all inventory sold in conjunction with the disposition of fixed assets,  and all
securities)  other  than (i) any  sale,  exchange  or other  disposition  in the
ordinary  course of  business  and (ii) any sale,  exchange  or  disposition  of
equipment utilized in the Borrower's business;

                  (g)  all extraordinary items; and

                  (h) any change in accruals for long-term  (more than one year)
personnel-related  costs, such as vacation time, pension liabilities and retiree
insurance.

                  "Effective  Date"  means  the  date  this  Agreement   becomes
effective in accordance with Section 10.9.

                  "Eligible  Assignee"  means  (i) any bank or  other  financial
institution  that is neither a Competitor  of the Borrower nor an Affiliate of a
Competitor of the Borrower and (ii) any Guarantor.

                  "Environmental  Claim" means all claims,  however asserted, by
any  Governmental  Authority or other  Person  alleging  potential  liability or
responsibility  for  violation  of any  Environmental  Law or for  injury to the
environment or threat to public health,  personal  injury  (including  sickness,
disease or death),  property  damage,  natural  resources  damage,  or otherwise
alleging  liability  or  responsibility  for damages  (punitive  or  otherwise),
cleanup,  removal,  remedial or response costs,  restitution,  civil or criminal
penalties,  injunctive relief, or other type of relief,  resulting from or based
upon (a) the  presence,  placement,  discharge,  emission or release  (including
intentional  and   unintentional,   negligent  and   non-negligent,   sudden  or
non-sudden,  accidental or non-accidental placements, spills, leaks, discharges,
emissions  or  releases)  of any  Hazardous  Material  at, in or from  property,
whether or not owned by the Borrower, or (b) any other circumstances forming the
basis of any violation, or alleged violation, of any Environmental Law.

                  "Environmental  Laws"  means all  applicable  federal,  state,
local and foreign laws, statutes, common law duties, judicial decisions,  rules,
regulations,  ordinances, judgements and codes, together with all administrative
orders, requests, licenses,  authorizations and permits of, and agreements with,
any Governmental Authorities,  in each case relating to the environment,  health
and  safety  or to  emissions,  discharges  or  releases,  or  the  manufacture,
distribution,  use,  treatment,  storage,  disposal,  transport or handling,  of
pollutants, contaminants, wastes or toxic or hazardous substances; including, as
they may be amended from time to time, the Comprehensive Environmental Response,
Compensation  and  Liability  Act of 1980  ("CERCLA"),  the Clean  Air Act,  the
Federal Water  Pollution  Control Act of 1972, the Solid Waste Disposal Act, the
Federal Resource Conservation and Recovery Act, the Toxic Substances Control Act
and the Emergency Planning and the Community Right-to-Know Act of 1986.


                                        8





                  "ERISA" means the Employee  Retirement  Income Security Act of
1974, as amended, or any successor statute.

                  "ERISA  Event" means (a) a Reportable  Event with respect to a
Qualified  Plan or a  Multiemployer  Plan; (b) a withdrawal by any member of the
Controlled Group from a Qualified Plan subject to Section 4063 of ERISA during a
plan  year in  which  it was a  substantial  employer  (as  defined  in  Section
4001(a)(2) of ERISA);  (c) a complete or partial withdrawal by any member of the
Controlled Group from a Multiemployer Plan; (d) the filing of a notice of intent
to terminate,  the treatment of a plan amendment as a termination  under Section
4041 or  4041A  of  ERISA  or the  commencement  of  proceedings  by the PBGC to
terminate a Qualified Plan or  Multiemployer  Plan subject to Title IV of ERISA;
(e)  a  failure  to  make  required   contributions   to  a  Qualified  Plan  or
Multiemployer Plan; (f) an event or condition which might reasonably be expected
to constitute grounds under Section 4042 of ERISA for the termination of, or the
appointment  of a trustee to  administer,  any Qualified  Plan or  Multiemployer
Plan;  (g) the imposition of any liability  under Title IV of ERISA,  other than
PBGC  premiums due but not  delinquent  under  Section  4007 of ERISA,  upon any
member of the Controlled  Group;  (h) an application for a funding waiver or any
extension of any  amortization  period  pursuant to Section 412 of the Code with
respect to any Qualified Plan; or (i) any member of the Controlled Group engages
in or otherwise becomes liable for a non-exempt prohibited transaction.

                  "Euro-Dollar  Business Day" means any Domestic Business Day on
which commercial banks are open for international  business  (including dealings
in dollar deposits) in London.

                  "Euro-Dollar  Lending  Office"  means,  as to each  Bank,  its
office,   branch  or  affiliate   located  at  its  address  set  forth  in  its
Administrative  Questionnaire (or identified in its Administrative Questionnaire
as its Euro-Dollar Lending Office) or such other office,  branch or affiliate of
such Bank as it may hereafter  designate as its  Euro-Dollar  Lending  Office by
notice to the Borrower and the Administrative Agent.

                  "Euro-Dollar  Loan" means (i) a Loan which bears interest at a
Euro-Dollar  Rate  pursuant to the  applicable  Notice of Borrowing or Notice of
Interest  Rate Election or (ii) an overdue  amount which was a Euro-Dollar  Loan
immediately before it became overdue.

                  "Euro-Dollar  Margin"  means a rate per  annum  determined  in
accordance with the Pricing Schedule.

                  "Euro-Dollar  Rate"  means  a  rate  of  interest   determined
pursuant to Section 2.5(b) on the basis of an Adjusted London Interbank  Offered
Rate.

                  "Euro-Dollar Reserve Percentage" has the meaning set forth
in Section 2.5(b).

                  "Event of Default" has the meaning set forth in Section 6.1.

                                        9





                  "Event of Loss" means, with respect to any Common
Collateral, any of the following:

                  (a) any loss, destruction or damage of or to any such property
         or asset, any condemnation, seizure or taking, by exercise of the power
         or eminent domain, thereof or the requisition of the use thereof; or

                  (b) any institution of any proceedings for the condemnation or
         seizure  of such  property  or asset for the  exercise  of any right of
         eminent domain.

                  "Excess  Cash Flow"  means,  for any fiscal year of the Parent
Guarantor, the excess (if any) of:

                           (A) the sum of (i)  EBITDA for such year and (ii) the
         amount of any decrease in Consolidated Net Working  Investment  between
         the beginning and the end of such year;

                  over

                           (B) the sum of (i) Consolidated  Capital Expenditures
         for such year, (ii)  Consolidated  Cash Interest Expense for such year,
         (iii) the amount of any increase in Consolidated Net Working Investment
         between the beginning and the end of such year, (iv) cash taxes paid by
         the Parent  Guarantor  Group  during  such year and (v)  scheduled  and
         optional  reductions of long-term  Indebtedness of the Parent Guarantor
         Group during such year (other than reductions of long-term Indebtedness
         under the Revolving  Credit  Agreement,  to the extent the  Commitments
         thereunder are not simultaneously reduced).

                  "FCC" means the Federal Communications Commission or any
successor thereto.

                  "FCC  License"  means  the  orders  from  the  FCC  listed  on
Attachment I to Exhibit B-2 hereto.

                  "Federal  Funds Rate"  means,  for any day, the rate per annum
(rounded  upward,  if  necessary,  to the  nearest  1/100th  of 1%) equal to the
weighted  average of the rates on  overnight  Federal  funds  transactions  with
members of the Federal  Reserve System arranged by Federal funds brokers on such
day,  as  published  by the  Federal  Reserve  Bank of New York on the  Domestic
Business Day next  succeeding  such day,  provided that (i) if such day is not a
Domestic Business Day, the Federal Funds Rate for such day shall be such rate on
such transactions on the next preceding Domestic Business Day as so published on
the next  succeeding  Domestic  Business  Day,  and  (ii) if no such  rate is so
published on such next succeeding  Domestic Business Day, the Federal Funds Rate
for such day shall be the average rate quoted to The Toronto-  Dominion  Bank on
such day on such transactions as determined by the Administrative Agent.


                                       10





                  "GAAP" means  generally  accepted  accounting  principles  set
forth in the opinions and pronouncements of the Accounting  Principles Board and
the American  Institute of  Certified  Public  Accountants  and  statements  and
pronouncements  of the Financial  Accounting  Standards  Board (or agencies with
similar  functions of  comparable  stature and authority  within the  accounting
profession),  or in such  other  statements  by such  other  entity as may be in
general use by significant segments of the U.S. accounting profession, which are
applicable to the circumstances as of the date of determination.

                  "Government  Approvals"  means any  authorizations,  consents,
approvals, licenses (including FCC licenses), leases, rulings, permits, tariffs,
rates,  certifications,  exemptions,  filings  or  registrations  by or with any
Governmental  Authority  required  to be obtained  or held by the  Borrower  and
related to the Project,  the execution,  delivery and performance of the Project
Documents or the creation,  perfection and enforcement of the Liens contemplated
by the Common Collateral Documents.

                  "Governmental  Authority" means any nation or government,  any
state or other  political  subdivision  thereof,  any  central  bank (or similar
monetary or regulatory  authority)  thereof,  any entity  exercising  executive,
legislative,  judicial,  regulatory or administrative functions of or pertaining
to government, and any corporation or other entity owned or controlled,  through
stock or capital ownership or otherwise, by any of the foregoing.

                  "Group of Loans" means at any time a group of Loans consisting
of (i) all Loans which are Base Rate Loans at such time or (ii) all  Euro-Dollar
Loans having the same Interest Period at such time,  provided that, if a Loan of
any  particular  Bank is  converted  to or made as a Base Rate Loan  pursuant to
Article 8, such Loan shall be included in the same Group or Groups of Loans from
time to time as it would have been in if it had not been so converted or made.

                  "Guarantor  Event" means either (i) delivery of a  Guarantor's
Notice (as defined in the Guaranty Issuance Agreement) to either the Borrower or
the  Administrative  Agent or (ii)  AMSC  having  requested  a  waiver  from the
Guarantors to permit the Guaranteed  Amount (as defined in the Guaranty Issuance
Agreement) at any time to increase to an amount not in excess of the  Guaranteed
Amount  that would  have been in effect at such time but for the  failure of the
Borrower  to meet any one or more of the  Performance  Tests (as  defined in the
Guaranty  Issuance  Agreement)  and such waiver not having  been  granted by the
Requisite  Guarantors (as defined in the Guaranty Issuance  Agreement) within 10
Business Days of receipt of such request.

                  "Guaranty Issuance Agreement" means the Guaranty Issuance
Agreement dated as of June 28, 1996, among Hughes, ST, Baron Capital,
the Borrower and the Parent Guarantor.

                  "Hazardous Materials" means all those substances which are
regulated by, or which may form the basis of liability under, any

                                       11





Environmental Law,  including all substances  identified under any Environmental
Law  as a  pollutant,  contaminant,  waste,  solid  waste,  hazardous  material,
hazardous  substance or toxic  substance,  including  petroleum or any petroleum
derived substance or byproduct.

                  "Hughes" means Hughes Electronics Corporation, a Delaware
corporation.

                  "Hughes  Guaranty"  means the  Guaranty,  dated as of June 28,
1996,  made by Hughes to the  Administrative  Agent for its own  benefit and the
benefit of the Banks and the banks party to the Revolving Credit  Agreement,  as
the same may be amended from time to time.

                  "Indebtedness"  of any Person means without  duplication,  (a)
all indebtedness for borrowed money; (b) all obligations  issued,  undertaken or
assumed as the deferred purchase price of capital assets;  (c) all reimbursement
obligations  with  respect  to  surety  bonds,   letters  of  credit,   bankers'
acceptances  and similar  instruments  (in each case,  whether or not  matured),
excluding  performance  bonds,  letters of credit and  similar  undertakings  in
connection with the construction, development or operation of the Project or any
other  business of the  Borrower,  to the extent that such  undertakings  do not
secure an  obligation  for borrowed  money or the deferred  purchase  price of a
capital asset;  (d) all  obligations  evidenced by notes,  bonds,  debentures or
similar instruments,  including  obligations so evidenced incurred in connection
with the acquisition of property,  assets or businesses,  excluding  performance
bonds,  letters  of credit  and  similar  undertakings  in  connection  with the
construction,  development  or operation of the Project or any other business of
the Borrower,  to the extent that such  undertakings do not secure an obligation
for borrowed money or the deferred  purchase  price of a capital asset;  (e) all
indebtedness  created  or  arising  under any  conditional  sale or other  title
retention  agreement,  or incurred as financing,  in either case with respect to
property  acquired  by the Person  (even  though the rights and  remedies of the
seller or bank  under such  agreement  in the event of  default  are  limited to
repossession or sale of such property);  (f) all Capital Lease Obligations;  (g)
all  net  obligations  with  respect  to  Rate  Contracts;   (h)  sale-leaseback
financings; (i) all Contingent Obligations; and (j) all Indebtedness referred to
in  paragraphs  (a)  through  (i) above  secured by any Lien upon or in property
(including  accounts and contract rights) owned by such Person, even though such
Person has not assumed or become  liable for the  payment of such  Indebtedness.
For purposes of this  definition,  (i) any  Indebtedness  of the Borrower to the
Parent  Guarantor  which  is  subordinated  to  the  Obligations  on  terms  and
conditions  satisfactory to the Agents, (ii) any Indebtedness of the Borrower to
a Subsidiary  of the  Borrower,  (iii) any  Indebtedness  of a Subsidiary of the
Borrower to or from the Borrower or another  Subsidiary of the Borrower and (iv)
any Indebtedness of Skycell to the Parent  Guarantor or the Borrower  consisting
of loans of amounts  that would  otherwise  have been spent by the  Borrower  in
connection with its sales and marketing activities shall be excluded.

                  "Indemnitee" has the meaning set forth in Section 10.3(b).

                                       12





                  "Information  Memorandum"  means the confidential  descriptive
memorandum  dated April 10, 1995, as amended by the revised  business plan dated
May 17,  1996,  in each  case  furnished  to the  Banks in  connection  with the
transactions contemplated hereby.

                  "Intercreditor    Agreement"   means   the   AMSC   Subsidiary
Corporation  Intercreditor and Collateral Agency Agreement dated as of March 15,
1995 by and among the secured  parties from time to time party  thereto and Bank
of America National Trust and Savings  Association,  as Collateral Agent, as the
same,  subject  to Section  5.25,  may be  amended,  supplemented,  restated  or
otherwise modified from time to time.

                  "Interest  Coverage  Ratio" means, as of the end of any fiscal
quarter of the Parent  Guarantor,  the ratio of (i) EBITDA to (ii)  Consolidated
Cash Interest  Expense,  each for the four  consecutive  fiscal  quarters of the
Parent Guarantor Group ending on such date.

                  "Interest  Period"  means,  with  respect to each  Euro-Dollar
Loan, the period commencing on the date of borrowing specified in the applicable
Notice  of  Borrowing  or on the date  specified  in the  applicable  Notice  of
Interest Rate Election and ending one, two, three or six months  thereafter,  as
the Borrower may elect in the applicable notice; provided that:

                  (a) any  Interest  Period which would  otherwise  end on a day
         which is not a  Euro-Dollar  Business Day shall be extended to the next
         succeeding  Euro-Dollar  Business Day unless such Euro-Dollar  Business
         Day falls in another calendar month, in which case such Interest Period
         shall end on the next preceding Euro-Dollar Business Day;

                  (b) any Interest  Period which begins on the last  Euro-Dollar
         Business  Day of a  calendar  month (or on a day for which  there is no
         numerically  corresponding day in the calendar month at the end of such
         Interest  Period) shall,  subject to clause (c) below,  end on the last
         Euro-Dollar Business Day of a calendar month; and

                  (c)  if  any  Interest  Period  includes  a date  on  which  a
         scheduled  payment of  principal  of the Loans is  required  to be made
         under Section 2.4 but does not end on such date, then (i) the principal
         amount (if any) of each  Euro-Dollar Loan required to be repaid on such
         date shall  have an  Interest  Period  ending on such date and (ii) the
         remainder (if any) of each such Euro-Dollar Loan shall have an Interest
         Period determined as set forth above.

                  "Interim Notes" means the notes of the Borrower issued to
each of Morgan Guaranty Trust Company of New York and Toronto Dominion
(Texas), Inc. on April 22, 1996 and June 12, 1996.

                  "Investment"  means any  investment in any Person,  whether by
means of share purchase, capital contribution, loan, Contingent Obligation, time
deposit or otherwise (but not including any demand deposit).

                                       13





                  "Joint   Venture"   means   any   corporation,    association,
partnership,  joint venture or other business  entity of which more than 10% but
of which 50% or less of the voting stock or other  equity  interests is owned or
controlled  directly  or  indirectly  by  the  Parent  Guarantor  or  any of its
Subsidiaries.

                  "Launch Insurance" has the meaning set forth in Section
4.22.

                  "Launch  Services  Contract"  means the  Contract  for  Launch
Services between General Dynamics Launch Services, Inc. and the Borrower,  dated
as of May 12,  1992,  as the same,  subject to  Section  5.25,  may be  amended,
supplemented, restated or otherwise modified from time to time.

                  "Leverage  Ratio"  means,  as of any  date,  the  ratio of (i)
Indebtedness  of the Parent  Guarantor  Group as of such date to (ii) EBITDA for
the four most recent  consecutive  fiscal quarters of the Parent Guarantor Group
ended on or before such date.

                  "Lien"   means   any   mortgage,   deed  of   trust,   pledge,
hypothecation,  assignment,  charge or deposit  arrangement,  encumbrance,  lien
(statutory  or other) or  preference,  priority  or other  security  interest or
preferential  arrangement of any kind or nature whatsoever  (including,  without
limitation, those created by, arising under or evidenced by any conditional sale
or other title  retention  agreement,  the  interest of a lessor under a Capital
Lease  Obligation,  any financing lease having  substantially  the same economic
effect as any of the foregoing,  or the filing of any financing statement naming
the owner of the asset to which such lien  relates  as debtor,  under the UCC or
any comparable  law) and any contingent or other agreement to provide any of the
foregoing.

                  "Loan" means a Base Rate Loan or a Euro-Dollar Loan and
"Loans" means Base Rate Loans, Euro-Dollar Loans or both.

                  "Loan Documents" means this Agreement,  the Common  Collateral
Documents,  the Shareholder Guaranties,  the Baron Capital Letter of Credit, all
Rate  Contracts  between the Borrower  and any of the Banks and all  agreements,
instruments  and documents  executed and  delivered in  connection  herewith and
therewith, each as amended, supplemented, waived or otherwise modified from time
to time.

                  "London Interbank Offered Rate" has the meaning set forth in
Section 2.5(b).

                  "Major Casualty  Proceeds"  means (i) the aggregate  insurance
proceeds  received in connection with one or more related events by the Borrower
or any of its Subsidiaries under any insurance policy maintained by the Borrower
or any of its  Subsidiaries  covering  losses with  respect to tangible  real or
personal property or improvements or losses from business interruption

                                       14





or (ii) any award or other  compensation  with  respect to any  condemnation  of
property (or any transfer or  disposition  of property in lieu of  condemnation)
received  by the  Borrower  or any of its  Subsidiaries,  if the  amount of such
aggregate proceeds or award or other compensation exceeds $1,000,000.

                  "Material  Adverse Effect" means a material adverse change in,
or a  material  adverse  effect  upon,  any of  (a)  the  operations,  business,
properties,  condition  (financial or otherwise) of either the Parent  Guarantor
Group taken as a whole or the  Borrower and its  Subsidiaries  taken as a whole;
(b) the ability or prospective  ability of the Parent  Guarantor or the Borrower
to perform under any Loan  Document or any material  Project  Document;  (c) the
legality,  validity,  binding effect or enforceability of any Loan Document;  or
(d) the  perfection  or  priority of any Lien  granted to the Common  Collateral
Agent under any of the Collateral Documents.

                  "Multiemployer  Plan" means a "multiemployer plan" (within the
meaning of Section  4001(a)(3)  of ERISA) to which any member of the  Controlled
Group makes, is making,  or is obligated to make  contributions  or has made, or
been obligated to make, contributions.

                  "Net Cash  Proceeds"  means,  with  respect  to any  Reduction
Event, an amount equal to the cash proceeds  received by the Parent Guarantor or
any of its  Subsidiaries  from or in respect of such Reduction Event  (including
any cash  proceeds  received  as income or other cash  proceeds  of any  noncash
proceeds of any Asset Sale), less (x) any expenses  reasonably  incurred by such
Person in respect of such Reduction  Event and (y) if such Reduction Event is an
Asset Sale,  (I) the amount of any  Indebtedness  secured by a Permitted Lien on
any asset  disposed  of in such  Asset  Sale and  discharged  from the  proceeds
thereof  and (II) any taxes  actually  paid or to be payable by such  Person (as
estimated by a senior financial or accounting  officer of the Parent  Guarantor,
giving effect to the overall tax position of the Parent Guarantor) in respect of
such Asset Sale.

                  "Net Revenues"  means,  for any period,  the gross revenues of
the Parent Guarantor Group net of all amounts paid as commissions to or withheld
by agents of the Parent  Guarantor  Group in respect of sales of the services of
Parent  Guarantor Group and to resellers of the services of the Parent Guarantor
Group.

                  "Notes" means promissory notes of the Borrower,  substantially
in the form of Exhibit A hereto,  evidencing  the  obligation of the Borrower to
repay the  Loans,  and  "Note"  means any one of such  promissory  notes  issued
hereunder.

                  "Notice of Amount of Secured Obligations" means a Notice of
Amount of Secured Obligations pursuant to the Intercreditor Agreement,
in the form of Exhibit E-1 hereto.

                  "Notice of Borrowing" has the meaning set forth in Section
2.2(a).

                                       15





                  "Notice of Interest Rate Election" has the meaning set forth
in Section 2.8(a).

                  "Notice  of Lien"  means  any  "notice  of  lien"  or  similar
document intended to be filed or recorded with any court,  registry,  recorder's
office,  central  filing  office or  Governmental  Authority  for the purpose of
evidencing,  creating,  perfecting or preserving the priority of a Lien securing
obligations owing to a Governmental Authority.

                  "Notice of New  Secured  Party"  means a Notice of New Secured
Party  pursuant  to the  Intercreditor  Agreement,  in the form of  Exhibit E- 2
hereto.

                  "Obligations"   means  all  Loans,  and  other   Indebtedness,
advances,  debts,  liabilities,  and  obligations,  owing by the Borrower to any
Bank, any Agent, or any other Person  required to be indemnified  under any Loan
Document, of any kind or nature,  present or future, whether or not evidenced by
any note, guaranty or other instrument,  arising under this Agreement, under any
other Loan Document, whether or not for the payment of money, whether arising by
reason of an  extension of credit,  loan,  guaranty,  indemnification  or in any
other  manner,   whether  direct  or  indirect   (including  those  acquired  by
assignment),  absolute  or  contingent,  due or to become due,  now  existing or
hereafter arising and however acquired.

                  "Parent" means, with respect to any Bank, any Person
controlling such Bank.

                  "Parent Guarantor" means American Mobile Satellite
Corporation, a Delaware corporation, and its successors.

                  "Parent  Guarantor  Group" means the Parent  Guarantor and its
Consolidated  Subsidiaries  other than the Second Satellite  Subsidiary.  At any
time when the Second Satellite Subsidiary is existing,  the information required
to be  delivered  pursuant  to Section  5.1(a) and (b) shall  exclude the Parent
Guarantor's  Investment in the Second Satellite Subsidiary,  and may be prepared
on a combined rather than a consolidated basis.

                  "Participant" has the meaning set forth in Section 10.6(b).

                  "PBGC" means the Pension Benefit  Guaranty  Corporation or any
entity succeeding to any or all of its functions under ERISA.

                  "Permitted  Capital  Lease"  means a capital  lease  permitted
pursuant to Section 5.26(a) or (c).

                  "Permitted Disposition" has the meaning set forth in Section
5.18.

                  "Permitted Investments" means the Investments permitted by
Section 5.21.

                                       16





                  "Permitted Liens" has the meaning set forth in Section 5.17.

                  "Person"  means  an  individual,  a  corporation,   a  limited
liability company, a partnership, an association, a trust or any other entity or
organization,  including a government or political  subdivision  or an agency or
instrumentality thereof.

                  "Plan"  means an employee  benefit plan (as defined in Section
3(3) of ERISA) which any member of the Controlled Group sponsors or maintains or
to which any  member  of the  Controlled  Group  makes or is  obligated  to make
contributions and includes any Multiemployer Plan or Qualified Plan.

                  "Pricing Schedule" means the applicable Schedule attached
hereto identified as such.

                  "Principal Repayment Date" has the meaning set forth in
Section 2.4.

                  "Principal Subsidiary" means at any time any Subsidiary of the
Parent  Guarantor,   except  (i)  the  Second  Satellite   Subsidiary  and  (ii)
Subsidiaries which at such time have been designated by the Parent Guarantor (by
notice to the  Administrative  Agent, which may be amended from time to time) as
nonmaterial  and which,  if aggregated  and  considered as a single  subsidiary,
would not meet the definition of a "significant  subsidiary" contained as of the
date hereof in Regulation S-X of the Securities and Exchange Commission.

                  "Principal  Subsidiary  Guaranty" means a continuing  guaranty
executed and delivered by a Principal  Subsidiary  substantially  in the form of
Exhibit F hereto.

                  "Prime Rate" means the rate of interest publicly  announced by
The Toronto-Dominion Bank in New York City from time to time as its Prime Rate.

                  "Project" means, collectively, the construction,  acquisition,
financing and operation, as contemplated by the Information  Memorandum,  of the
Satellite and the CGS, all data and documentation and all ancillary  structures,
equipment and systems related  thereto or which is realty,  fixtures or personal
property  owned or leased by the  Borrower in respect of the  Satellite  and the
CGS.

                  "Project  Documents"  means,  as of  any  date,  collectively,
subject to Section 5.25, (i) the Loan  Documents,  (ii) the agreements set forth
on Schedule II hereto,  and (iii) any other agreement or instrument entered into
from time to time after the date hereof  materially  affecting  the financing or
operation of the Satellite or the CGS.

                  "Proof of Loss  Statement"  means the Proof of Loss  Statement
dated April 10,  1996, a copy of which has been  delivered to the  Documentation
Agent


                                       17





                  "Qualified  Plan" means a pension  plan (as defined in Section
3(2) of ERISA) intended to be tax-qualified under Section 401(a) of the Code and
which any member of the Controlled  Group  sponsors,  maintains,  or to which it
makes or is obligated to make  contributions  or has made  contributions  at any
time during the  immediately  preceding  period  covering at least five (5) plan
years, but excluding any Multiemployer Plan.

                  "Quarterly  Date" means March 31,  June 30,  September  30 and
December 31.

                  "Rate   Contracts"  means  interest  rate  and  currency  swap
agreements, cap, floor and collar agreements,  interest rate insurance, currency
spot and forward  contracts  and other  agreements or  arrangements  designed to
provide protection against  fluctuations in interest or currency exchange rates;
provided  that such  agreements  or  arrangements  are  documented  under master
netting agreements.

                  "Reduced  Leverage Date" means the first Domestic Business Day
as of which the Leverage Ratio, determined as of the last day of each of the two
most recently ended fiscal quarters of the Borrower, is less than 5.0 to 1.

                  "Reduction   Event"  means  (i)  any  Asset  Sale,   (ii)  the
incurrence  of  any   Indebtedness  by  the  Parent  Guarantor  or  any  of  its
Subsidiaries,  other than Indebtedness permitted pursuant to Section 5.22, (iii)
the  issuance of any equity  securities  by the Parent  Guarantor  or any of its
Subsidiaries  (other than  equity  securities  (w) issued  pursuant to any stock
option,  stock  purchase  or other plan  intended to benefit or  compensate  the
officers,  directors or employees of the Parent  Guarantor,  the Borrower or any
Principal Subsidiary,  but only to the extent that the Net Cash Proceeds thereof
in any  fiscal  year  of the  Parent  Guarantor  do not  exceed  the  sum of (A)
$2,000,000  plus (B) the  aggregate  amount by which such Net Cash Proceeds were
less than $2,000,000 in each prior fiscal year of the Parent Guarantor after the
date hereof, (x) issued to the Parent Guarantor or any of its Subsidiaries,  (y)
the Net Cash  Proceeds of which are  invested in the  Borrower by means of share
purchase or capital  contribution or (z) are issued by the Parent  Guarantor and
the Net Cash Proceeds of which are invested in accordance with Section  5.21(f))
or (iv) receipt of Major Casualty  Proceeds.  The description of any transaction
as falling  within the above  definition  does not affect any limitation on such
transaction imposed by Article 5 of this Agreement.

                  "Reduction  Percentage" means, (i) in respect of an Asset Sale
or an  incurrence  of  Indebtedness,  100%;  (ii) in respect  of Major  Casualty
Proceeds,  100% of the  amount  in  excess  of the  Retained  Amount;  provided,
however,  that the Reduction  Percentage with respect to Major Casualty Proceeds
received in connection with an Event of Loss involving  Common  Collateral shall
be  the  Banks'   "Proportionate   Share"  (as  such  term  is  defined  in  the
Intercreditor  Agreement) of such proceeds;  and (iii) in respect of Excess Cash
Flow or the issuance of equity securities not constituting Indebtedness,  75% to
but excluding the Reduced Leverage Date and 50% thereafter.

                                       18





                  "Reference Banks" means the principal London offices of Morgan
Guaranty Trust Company of New York, The Toronto-Dominion Bank and any other Bank
which is appointed a Reference  Bank by the Agents after  consultation  with the
Borrower, and "Reference Bank" means any one of such Reference Banks.

                  "Regulation U" means Regulation U of the Board of Governors of
the Federal Reserve System, as in effect from time to time.

                  "Release   Date"  means  the  first  date  (a)  that  (i)  the
performance  tests set forth on the Release Date Schedule have been met and (ii)
the sum of the amount of Major  Casualty  Proceeds  and the  portion of Net Cash
Proceeds of the  issuance  of equity  securities  not  required to be applied to
prepayment  of the Loans  pursuant to Section  2.4(b)(i),  in each case received
after May 1, 1996, equals or exceeds  $60,000,000 and (b) on and as of which, no
Default  shall have  occurred  and be  continuing  and the  representations  and
warranties of the Borrower and the Parent Guarantor  contained in this Agreement
and the Common Collateral Documents shall be true.

                  "Release Date Schedule" means the Schedule attached hereto
and designated as such.

                  "Reportable  Event"  means  any of the  events  set  forth  in
Section 4043 of ERISA or the  regulations  thereunder,  a withdrawal from a Plan
described in Section 4063 of ERISA,  or a cessation of  operations  described in
Section 4062(e) of ERISA.

                  "Required  Banks"  means at any time Banks having at least 51%
of the aggregate  amount of the Commitments  or, if the  Commitments  shall have
been  terminated,  holding Notes evidencing at least 51% of the aggregate unpaid
principal amount of the Loans.

                  "Required  Release  Banks"  means at any time Banks  having at
least 80% of the  aggregate  amount of the  Commitments  or, if the  Commitments
shall  have  been  terminated,  holding  Notes  evidencing  at least  80% of the
aggregate unpaid principal amount of the Loans.

                  "Requirement  of  Law"  means,  as  to  any  Person,  any  law
(statutory  or  common),  treaty,  rule or  regulation  or  determination  of an
arbitrator or of a Governmental Authority, in each case applicable to or binding
upon the  Person or any of its  property  or to which  the  Person or any of its
property is  subject;  in any case,  non-compliance  with which by either of the
Parent  Guarantor  or the Borrower or their  Subsidiaries  could  reasonably  be
expected to have a Material Adverse Effect.

                  "Responsible  Officer" means, with respect to any Person,  the
Chief Executive  Officer,  the President or a duly authorized Vice President or,
with respect to financial matters, the Chief Financial Officer or the Treasurer,
of such Person.


                                       19





                  "Retained Amount" means the first $60,000,000 in the aggregate
of Net Cash Proceeds from insurance  receipts and equity  issuances  received by
the Borrower after May 1, 1996.

                  "Revolving  Credit Agreement" means the Credit Agreement dated
as of the date hereof among the Borrower,  the Parent Guarantor,  the Agents and
the  other  banks  party  thereto,  as the  same may be  amended,  supplemented,
restated or otherwise modified from time to time.

                  "Sales Co." means AMSC Sales Corporation, Ltd., a U.S.
Virgin Islands corporation.

                  "Satellite" means the AMSC MSAT Satellite launched April 7,
1995.

                  "Second Satellite Subsidiary" has the meaning set forth in
Section 5.21(f).

                  "Shareholder Guarantors" means Hughes, ST and Baron Capital.

                  "Shareholder Guaranties" means the Hughes Guaranty, the ST
Guaranty and the Baron Capital Guaranty.

                  "Skycell" means AMSC Skycell, Inc., a Delaware corporation.

                  "ST" means  Singapore  Telecommunications  Ltd., a corporation
organized under the laws of Singapore.

                  "ST Guaranty"  means the Guaranty,  dated as of June 28, 1996,
made by ST to the  Administrative  Agent for its own  benefit and the benefit of
the Banks and the banks party to the Revolving Credit Agreement, as the same may
be amended from time to time.

                  "Subscribers" means, as of any date, the sum of (i) the number
of mobile communication  terminals (x) which are regularly billed subscribers to
one of the  Borrower's  mobile  communications  services  as of such  date,  (y)
invoices from the Borrower with respect to which have been  outstanding  no more
than 60 days  (measured from the date of original  issuance  thereof) as of such
date  and are  billed  at the  rate  normally  billed  as of such  date  for the
Borrower's  mobile  communication  services to which such  mobile  communication
terminals are  subscribed  and (z) which are not test units and (ii)  Equivalent
Qualifying  Subscribers  as of such  date.  For  purposes  of  this  definition,
"Equivalent Qualifying Subscribers" means, in the case of bulk capacity sales of
the  Borrower's  services,  the sum of each  number  obtained  by  dividing  the
aggregate  annual  revenue  from each  sale,  as  reasonably  determined  by the
Borrower,  by the Average Annual  Revenue Per  Subscriber,  and "Average  Annual
Revenue Per Subscriber"  means, (x) in the case of sales of satellite  telephone
services,  $1,950,  (y) in the case of sales of private voice network  services,
$750, and (z) in the case of sales of mobile message services, $500.


                                       20





                  "Subsidiary" means, as to any Person, any corporation or other
entity of which  securities or other ownership  interests having ordinary voting
power to elect a majority of the board of directors or other persons  performing
similar functions are at the time directly or indirectly owned by such Person.

                  "UCC" means the Uniform Commercial Code as in effect in any
jurisdiction.

                  "Unfunded  Pension  Liabilities"  means the excess of a Plan's
accrued  benefits,  as defined in Section 3(23) of ERISA, over the current value
of that Plan's assets, as defined in Section 3(26) of ERISA.

                  "United States" means the United States of America,  including
the States and the District of  Columbia,  but  excluding  its  territories  and
possessions.

                  "Vendor Debt" means all  Indebtedness  of the Borrower and its
Consolidated  Subsidiaries under (i) the Credit Agreement dated as of August 31,
1992,  by and  among the  Borrower,  the banks  signatory  thereto,  and Bank of
America  National  Trust and Savings  Association,  as agent for such banks,  as
amended through the date hereof, (ii) the Deferred Payment Agreement between the
Borrower and Westinghouse  Electric  Corporation dated as of September 15, 1992,
as amended  through the date hereof,  and (iii) the Term Loan Agreement  between
the Borrower and Northern Telecom Finance  Corporation dated as of May 28, 1993,
as amended through the date hereof.

                  "Withdrawal  Liabilities" means, as of any determination date,
the aggregate  amount of the  liabilities,  if any,  pursuant to Section 4201 of
ERISA if the Controlled Group made a complete  withdrawal from all Multiemployer
Plans and any increase in contributions pursuant to Section 4243 of ERISA.

                  SECTION  0.2.  Accounting  Terms  and  Determinations.  Unless
otherwise   specified  herein,   all  accounting  terms  used  herein  shall  be
interpreted,  all  accounting  determinations  hereunder  shall be made, and all
financial  statements  required to be delivered  hereunder  shall be prepared in
accordance  with  GAAP as in  effect  from  time  to  time,  applied  on a basis
consistent  (except for changes  concurred in by the Parent  Guarantor's and the
Borrower's   independent  public  accountants)  with  the  most  recent  audited
consolidated or combined financial statements of each the Parent Guarantor,  the
Parent Guarantor Group or the Borrower and its Consolidated Subsidiaries, as the
case may be,  delivered to the Banks;  provided that, if the Parent Guarantor or
the  Borrower  notifies  the  Administrative  Agent  that it wishes to amend the
definition  of "Excess Cash Flow" in Section 1.1 or any covenant in Article 5 to
eliminate the effect of any change in GAAP on the operation of such covenant (or
if the Administrative  Agent notifies the Parent Guarantor and the Borrower that
the  Required  Banks wish to amend  Section 1.1 or Article 5 for such  purpose),
then the Parent  Guarantor's  and the Borrower's  compliance  with such covenant
shall be  determined  on the  basis of GAAP in  effect  immediately  before  the
relevant change in GAAP became effective, until either such notice is

                                       21





withdrawn  or such  covenant is amended in a manner  satisfactory  to the Parent
Guarantor, the Borrower and the Required Banks.


                                    ARTICLE 1

                                   THE CREDITS

                  SECTION  1.1.  Commitments  to Lend.  During the  Availability
Period,  each Bank  severally  agrees,  on the terms and conditions set forth in
this Agreement,  to lend to the Borrower from time to time amounts not to exceed
in the aggregate the amount of its Commitment. Each Borrowing under this Section
shall be in an aggregate  principal amount of $10,000,000 or any larger multiple
of $1,000,000  (except that any such Borrowing may be in the aggregate amount of
the unused  Commitments)  and shall be made from the  several  Banks  ratably in
proportion to their respective Commitments. The Commitments are not revolving in
nature, and amounts repaid or prepaid may not be reborrowed.

                  SECTION 1.2. Method of Borrowing.  (a) The Borrower shall give
the Administrative Agent irrevocable telephonic notice, confirmed immediately in
writing  (a  "Notice of  Borrowing"),  not later than 10:30 A.M.  (New York City
time) on (x) the Domestic  Business Day before each Base Rate  Borrowing and (y)
the  third   Euro-Dollar   Business  Day  before  each  Euro-Dollar   Borrowing,
specifying:

                         (i) the  date  of  such  Borrowing,  which  shall  be a
         Domestic  Business  Day  in the  case  of a Base  Rate  Borrowing  or a
         Euro-Dollar Business Day in the case of a Euro-Dollar Borrowing;

                        (ii) the aggregate amount of such Borrowing;

                       (iii)  whether the Loans comprising such Borrowing are
         to bear interest initially at the Base Rate or a Euro-Dollar Rate;
         and

                        (iv)  in  the  case  of  a  Euro-Dollar  Borrowing,  the
         duration of the  Interest  Period  applicable  thereto,  subject to the
         provisions of the definition of Interest Period.

In no  event  shall  the  total  number  of  Groups  of  Loans  at any one  time
outstanding exceed seven.

                  (b) Upon receipt of a Notice of Borrowing,  the Administrative
Agent shall promptly notify each Bank of the contents thereof and of such Bank's
ratable  share  of such  Borrowing  and  such  Notice  of  Borrowing  shall  not
thereafter be revocable by the Borrower.

                  (c) Not later than 12:00 Noon (New York City time) on the date
of each  Borrowing,  each Bank shall make  available  its ratable  share of such
Borrowing, in Federal or other funds immediately available in New York City, to

                                       22





the Administrative  Agent at its address referred to in Section 10.1. Unless the
Administrative  Agent  determines  that any  applicable  condition  specified in
Article 3 has not been satisfied,  the Administrative  Agent will make the funds
so received  from the Banks  available  to the  Borrower  at the  Administrative
Agent's aforesaid address.

                  (d) Unless the Administrative Agent shall have received notice
from a Bank  prior to the date of any  Borrowing  that  such  Bank will not make
available to the Administrative  Agent such Bank's share of such Borrowing,  the
Administrative  Agent may assume that such Bank has made such share available to
the  Administrative  Agent  on the date of such  Borrowing  in  accordance  with
subsection  (c) of this  Section and the  Administrative  Agent may, in reliance
upon  such   assumption,   make  available  to  the  Borrower  on  such  date  a
corresponding amount. If and to the extent that such Bank shall not have so made
such share  available to the  Administrative  Agent,  such Bank and the Borrower
severally  agree to repay to the  Administrative  Agent forthwith on demand such
corresponding  amount together with interest thereon, for each day from the date
such  amount is made  available  to the  Borrower  until the date such amount is
repaid to the Administrative  Agent, at (i) in the case of the Borrower,  a rate
per annum equal to the higher of the Federal  Funds Rate and the  interest  rate
applicable  thereto  pursuant  to Section 2.5 and (ii) in the case of such Bank,
the Federal  Funds Rate.  If such Bank shall repay to the  Administrative  Agent
such  corresponding  amount,  such amount so repaid shall constitute such Bank's
Loan included in such Borrowing for purposes of this Agreement.

                  SECTION  1.3.  Notes.  (a) The  Loans  of each  Bank  shall be
evidenced  by a single Note payable to the order of such Bank for the account of
its  Applicable  Lending  Office  in an  amount  equal to the  aggregate  unpaid
principal amount of such Bank's Loans.

                  (b)  Each  Bank  may,  by  notice  to  the  Borrower  and  the
Administrative  Agent,  request that its Loans of a particular type be evidenced
by a separate Note in an amount equal to the aggregate  unpaid  principal amount
of such Loans.  Each such Note shall be in  substantially  the form of Exhibit A
hereto with  appropriate  modifications  to reflect  the fact that it  evidences
solely  Loans of the relevant  type.  Each  reference  in this  Agreement to the
"Note" of such Bank shall be deemed to refer to and  include  any or all of such
Notes, as the context may require.

                  (c) Upon  receipt  of each  Bank's  Note  pursuant  to Section
3.1(a), the Documentation  Agent shall forward such Note to such Bank. Each Bank
shall record the date,  amount and type of each Loan made by it and the date and
amount of each payment of principal  made by the Borrower with respect  thereto,
and may, if such Bank so elects in connection  with any transfer or  enforcement
of its  Note,  endorse  on the  schedule  forming  a  part  thereof  appropriate
notations to evidence the foregoing  information  with respect to each such Loan
then  outstanding;  provided  that  the  failure  of any  Bank to make  any such
recordation  or  endorsement  shall not affect the  obligations  of the Borrower
hereunder or under the Notes. Each Bank is hereby irrevocably authorized

                                       23





by the  Borrower  so to endorse its Note and to attach to and make a part of its
Note a continuation of any such schedule as and when required.

                  SECTION 1.4.  Maturity of Loans; Mandatory Prepayments.  (a)
The Borrower shall repay, and there shall become due and payable, on
each Quarterly Date commencing March 31, 1999 through and including June
30, 2001 (a "Principal Repayment Date"), an aggregate principal amount
of the Loans equal to one-tenth of the principal amount of Loans
outstanding immediately after the termination of the Commitments
pursuant to Section 2.9; provided that in any event the outstanding
Loans shall be repaid in full not later than the last Principal
Repayment Date.  Each such payment shall be applied to such Group or
Groups of Loans as the Borrower may designate in the applicable Notice
of Borrowing or Notice of Interest Rate Election (or, failing such
designation, as determined by the Administrative Agent), and shall be
applied to repay ratably the Loans of the several Banks included in such
Group or Groups.  No prepayment of Loans pursuant to Section 2.10 shall
reduce the amount of any subsequent mandatory prepayment pursuant to
this Section.

                  (b)  (i)  In addition, the Loans shall be prepaid in the
         following amounts:

                                    (x) in the event that the  Parent  Guarantor
                  or any of its Subsidiaries  shall at any time, or from time to
                  time,   receive  after  the  date  of  the  initial  Borrowing
                  hereunder  any Net Cash Proceeds of any  Reduction  Event,  an
                  amount  equal  to the  Reduction  Percentage  of such Net Cash
                  Proceeds; and

                                    (y) an amount,  for each  fiscal year of the
                  Parent  Guarantor  and its  Consolidated  Subsidiaries  ending
                  after the date of the initial  Borrowing  hereunder,  equal to
                  the Reduction Percentage of Excess Cash Flow for such fiscal
                  year.

                      (ii) The  prepayments  required  by clause  (i)(x) of this
         subsection shall be made forthwith upon receipt by the Parent Guarantor
         or any of its  Subsidiaries,  as the  case  may be,  of such  Net  Cash
         Proceeds;  provided  that if the  Reduction  Percentage of the Net Cash
         Proceeds  in respect of any  Reduction  Event is less than  $1,000,000,
         such prepayment  shall be made upon receipt of proceeds that,  together
         with all other such  amounts  not  previously  applied,  equal at least
         $1,000,000;  and  provided  further that if any such  prepayment  would
         otherwise require  prepayment of Euro- Dollar Loans or portions thereof
         prior to the last day of the related Interest  Period,  such prepayment
         shall, unless the Borrower otherwise notifies the Administrative  Agent
         or the  Administrative  Agent otherwise  notifies the Borrower upon the
         instructions  of the Required  Banks, be deferred to such last day. The
         prepayments  required by clause (i)(y) of this subsection shall be made
         on the first Euro-Dollar Business Day on or after April 15 of the next

                                       24





         succeeding  fiscal  year.  The Borrower  shall give the  Administrative
         Agent  at  least  five  Euro-Dollar   Business  Days'  notice  of  each
         prepayment of Euro-Dollar Loans required pursuant to this subsection.

                     (iii)  The  amount  of  any  prepayment  pursuant  to  this
         subsection  shall  be  applied  to  reduce  the  amount  of  subsequent
         scheduled  prepayments of the Loans pursuant to subsection (a) above as
         follows:

                                 (x) in the case of  prepayments  resulting from
                          an  incurrence  of  Indebtedness  or the  issuance  of
                          equity securities,  the amount of each such prepayment
                          shall be applied to scheduled prepayments of the Loans
                          ratably by amount to reduce each  remaining  scheduled
                          prepayment thereof; and

                                 (y) in the case of all other  prepayments,  the
                          amount of each such  prepayment  shall be  applied  to
                          scheduled prepayments of the Loans in inverse order of
                          maturity.



                  SECTION  1.5.  Interest  Rates.  (a) Each Base Rate Loan shall
bear interest on the outstanding principal amount thereof, for each day from the
date such Loan is made until it becomes  due,  at a rate per annum  equal to the
sum of (x) the  Base  Rate  Margin  plus (y) the Base  Rate for such  day.  Such
interest shall be payable  quarterly in arrears on each Quarterly Date and, with
respect to the principal amount of any Base Rate Loan converted to a Euro-Dollar
Loan, on each date a Base Rate Loan is so converted. Any overdue principal of or
interest on any Base Rate Loan shall bear interest,  payable on demand, for each
day  until  paid at a rate  per  annum  equal  to the sum of 2%  plus  the  rate
otherwise applicable to Base Rate Loans for such day.

                  (b)  Each   Euro-Dollar   Loan  shall  bear  interest  on  the
outstanding  principal amount thereof,  for each day during each Interest Period
applicable  thereto,  at a rate per  annum  equal to the sum of the  Euro-Dollar
Margin for such day plus the Adjusted London  Interbank  Offered Rate applicable
to such Interest Period. Such interest shall be payable for each Interest Period
on the last day  thereof  and,  if such  Interest  Period is longer  than  three
months, at intervals of three months after the first day thereof.

                  The "Adjusted London Interbank Offered Rate" applicable to any
Interest Period means a rate per annum equal to the quotient  obtained  (rounded
upward,  if  necessary,  to the next  higher  1/100 of 1%) by  dividing  (i) the
applicable  London  Interbank  Offered  Rate by (ii) 1.00 minus the  Euro-Dollar
Reserve Percentage.

                  The "London Interbank Offered Rate" applicable to any Interest
Period means the average (rounded upward, if necessary, to the next higher 1/16

                                       25





of 1%) of the  respective  rates  per annum at which  deposits  in  dollars  are
offered  to each of the  Reference  Banks  in the  London  interbank  market  at
approximately 11:00 A.M. (London time) two Euro-Dollar  Business Days before the
first  day of such  Interest  Period  in an  amount  approximately  equal to the
principal  amount of the  Euro-Dollar  Loan of such Reference Bank to which such
Interest Period is to apply and for a period of time comparable to such Interest
Period.

                  "Euro-Dollar  Reserve  Percentage"  means  for  any  day  that
percentage  (expressed  as a  decimal)  which  is in  effect  on  such  day,  as
prescribed  by the Board of  Governors  of the  Federal  Reserve  System (or any
successor) for determining the maximum reserve  requirement for a member bank of
the Federal Reserve System in New York City with deposits exceeding five billion
dollars  in respect of  "Eurocurrency  liabilities"  (or in respect of any other
category  of  liabilities  which  includes  deposits by  reference  to which the
interest rate on  Euro-Dollar  Loans is determined or any category of extensions
of credit or other assets which includes loans by a non-United  States office of
any Bank to United States residents). The Adjusted London Interbank Offered Rate
shall be adjusted automatically on and as of the effective date of any change in
the Euro-Dollar Reserve Percentage.

                  (c) Any overdue  principal  of or interest on any  Euro-Dollar
Loan shall bear interest,  payable on demand,  for each day until paid at a rate
per annum equal to the higher of (i) the sum of 2% plus the Euro- Dollar  Margin
for such day plus the quotient obtained  (rounded upward,  if necessary,  to the
next  higher  1/100 of 1%) by  dividing  (x) the  average  (rounded  upward,  if
necessary,  to the next higher 1/16 of 1%) of the respective  rates per annum at
which one day (or, if such amount due remains unpaid more than three Euro-Dollar
Business Days,  then for such other period of time not longer than six months as
the  Administrative   Agent  may  select)  deposits  in  dollars  in  an  amount
approximately  equal to such overdue  payment due to each of the Reference Banks
are  offered  to such  Reference  Bank in the  London  interbank  market for the
applicable period determined as provided above by (y) 1.00 minus the Euro-Dollar
Reserve  Percentage (or, if the circumstances  described in clause (a) or (b) of
Section  8.1 shall  exist,  at a rate per annum  equal to the sum of 2% plus the
rate applicable to Base Rate Loans for such day) and (ii) the sum of 2% plus the
Euro-Dollar  Margin for such day plus the Adjusted London Interbank Offered Rate
applicable to such Loan at the date such payment was due.

                  (d) The  Administrative  Agent shall  determine  each interest
rate  applicable to the Loans  hereunder.  The  Administrative  Agent shall give
prompt  notice  to the  Borrower  and the  participating  Banks of each  rate of
interest so determined, and its determination thereof shall be conclusive in the
absence of manifest error.

                  (e) Each  Reference  Bank  agrees to use its best  efforts  to
furnish quotations to the Administrative  Agent as contemplated by this Section.
If any Reference Bank does not furnish a timely  quotation,  the  Administrative
Agent shall  determine the relevant  interest rate on the basis of the quotation
or quotations  furnished by the remaining Reference Bank or Banks or, if none of
such  quotations is available on a timely basis,  the  provisions of Section 8.1
shall apply.


                                       26




                  SECTION 1.6. Commitment Fees. During the Availability  Period,
the Borrower shall pay to the Administrative  Agent for the account of the Banks
ratably  in  proportion  to their  Commitments  a  commitment  fee  equal to the
Commitment  Fee  Percentage per annum of the daily amount by which the aggregate
amount of the Commitments exceeds the aggregate  outstanding principal amount of
the Loans.  Such  commitment  fee shall accrue from and  including the Effective
Date to but  excluding  the  date of  termination  of the  Commitments  in their
entirety,  and shall be payable  quarterly in arrears on each Quarterly Date and
on the date of termination of the Commitments in their entirety. For the purpose
of this Section,  "Commitment Fee  Percentage"  means 0.10% prior to the Release
Date and 0.50% thereafter.

                  SECTION 1.7. Optional Termination or Reduction of Commitments.
(a) During the  Availability  Period,  the  Borrower  may,  upon at least  three
Domestic  Business Days' notice to the  Administrative  Agent, (i) terminate the
Commitments  at any  time,  if no Loans  are  outstanding  at such  time or (ii)
ratably  reduce from time to time by an  aggregate  amount of  $10,000,000  or a
larger multiple of $1,000,000, the aggregate amount of the Commitments in excess
of the aggregate outstanding principal amount of the Loans.

                  (b) Upon  receipt of a notice of  reduction  pursuant  to this
Section,  the  Administrative  Agent  shall  promptly  notify  each  Bank of the
contents  thereof and of such Bank's  ratable  share of such  reduction and such
notice shall not thereafter be revocable by the Borrower.

                  SECTION 1.8. Method of Electing  Interest Rates. (a) The Loans
included in each  Borrowing  shall bear  interest  initially at the type of rate
specified by the Borrower in the applicable Notice of Borrowing. Thereafter, the
Borrower  may from time to time elect to change or continue the type of interest
rate borne by each Group of Loans  (subject  in each case to the  provisions  of
Article 8), as follows:

                   (i) if such Loans are Base Rate Loans, the Borrower may elect
         to  convert  such  Loans to  Euro-Dollar  Loans  as of any  Euro-Dollar
         Business Day and

                  (ii) if such Loans are  Euro-Dollar  Loans,  the  Borrower may
         elect to convert  such  Loans to Base Rate  Loans or elect to  continue
         such Loans as  Euro-Dollar  Loans for an  additional  Interest  Period,
         subject  to  Section  2.12  in the  case  of  any  such  conversion  or
         continuation  effective  on any day other than the last day of the then
         current Interest Period applicable to such Loans.

Each  such  election  shall be made by  giving  irrevocable  telephonic  notice,
confirmed  immediately in writing (a "Notice of Interest Rate  Election") to the
Administrative Agent not later than 10:30 A.M. (New York City time) on the third
Euro-Dollar Business Day before the

                                       27





conversion or continuation selected in such notice is to be effective.  A Notice
of Interest Rate  Election  may, if it so specifies,  apply to only a portion of
the aggregate principal amount of the relevant Group of Loans; provided that (i)
such portion is allocated ratably among the Loans comprising such Group and (ii)
the portion to which such Notice applies,  and the remaining portion to which it
does not apply, are each $10,000,000 or any larger multiple of $1,000,000.

                  (b)  Each Notice of Interest Rate Election shall specify:

                       (i) the Group of Loans (or portion thereof) to
                           which such notice applies;

                       (ii) the date on which  the  conversion  or  continuation
         selected in such notice is to be effective, which shall comply with the
         applicable clause of subsection (a) above;

                       (iii)  if  the  Loans  comprising  such  Group  are to be
         converted,  the new type of Loans and, if the Loans being converted are
         to be Euro-Dollar  Loans, the duration of the next succeeding  Interest
         Period applicable thereto; and

                       (iv) if such  Loans are to be  continued  as  Euro-Dollar
         Loans  for  an  additional   Interest  Period,  the  duration  of  such
         additional Interest Period.

Each  Interest  Period  specified in a Notice of Interest  Rate  Election  shall
comply with the  provisions of the  definition  of Interest  Period set forth in
Section 1.1.

                  (c) If, upon the expiration of any Interest Period  applicable
to any  Eurodollar  Loan, the Borrower has not given a timely Notice of Interest
Rate  Election  with  respect to such Loan,  the  Administrative  Agent shall be
deemed to have  received a Notice of Interest  Rate  Election  from the Borrower
with respect to such Loan  requesting  that such Loan be  converted  into a Base
Rate Loan on the last day of the Interest Period applicable to such Loan.

                  (d) Upon receipt of a Notice of Interest  Rate  Election  from
the Borrower pursuant to subsection (a) above or a deemed receipt of a Notice of
Interest Rate  Election  pursuant to subsection  (c) above,  the  Administrative
Agent shall  promptly  notify each Bank of the contents  thereof and such notice
shall not thereafter be revocable by the Borrower.

                  (e) An election by the Borrower to change or continue the rate
of interest  applicable to any Group of Loans pursuant to this Section shall not
constitute a "Borrowing" subject to the provisions of Section 3.3.

                  SECTION 1.9.  Mandatory Termination and Reduction of
Commitments.  The Commitments shall terminate on the earlier of (i) the
last day of the Availability Period and (ii) the occurrence of a Guarantor

                                       28





Event. If the Parent Guarantor or any of its Subsidiaries  shall at any time, or
from time to time, on or prior to the date of the initial  Borrowing  hereunder,
receive any Net Cash Proceeds of any Reduction Event,  the Commitments  shall be
reduced  ratably on the date of such receipt in an amount equal to the Reduction
Percentage of such Net Cash  Proceeds.  In addition,  the  Commitments  shall be
reduced  ratably in the amount and on the date of each  prepayment  pursuant  to
Section 2.4(b).

                  SECTION 1.10. Optional Prepayments. (a) Subject in the case of
any  Euro-Dollar  Borrowing to Section 2.12, the Borrower may, upon at least one
Domestic Business Day's notice to the Administrative  Agent, prepay any Group of
Base Rate Loans or upon at least three Euro- Dollar Business Days' notice to the
Administrative  Agent,  prepay any Group of Euro-Dollar  Loans,  in each case in
whole  at any  time,  or from  time to  time  in  part  in  amounts  aggregating
$10,000,000 or any larger multiple of $1,000,000, by paying the principal amount
to be prepaid  together with accrued interest thereon to the date of prepayment.
Each such optional  prepayment  shall be applied to prepay  ratably the Loans of
the several Banks included in such Group.

                  (b) Upon  receipt of a notice of  prepayment  pursuant to this
Section,  the  Administrative  Agent  shall  promptly  notify  each  Bank of the
contents  thereof and of such Bank's  ratable share of such  prepayment and such
notice shall not thereafter be revocable by the Borrower.

                  SECTION 1.11.  General Provisions as to Payments.  (a)  The
Borrower shall make each payment of principal of, and interest on, the
Loans and of fees hereunder, not later than 12:00 Noon (New York City
time) on the date when due, in Federal or other funds immediately
available in New York City, to the Administrative Agent at its address
referred to in Section 10.1.  The Administrative Agent will promptly
distribute to each Bank its ratable share of each such payment received
by the Administrative Agent for the account of the Banks.  Whenever any
payment of principal of, or interest on, the Base Rate Loans or of fees
shall be due on a day which is not a Domestic Business Day, the date for
payment thereof shall be extended to the next succeeding Domestic
Business Day.  Whenever any payment of principal of, or interest on, the
Euro-Dollar Loans shall be due on a day which is not a Euro-Dollar
Business Day, the date for payment thereof shall be extended to the next
succeeding Euro-Dollar Business Day unless such Euro-Dollar Business Day
falls in another calendar month, in which case the date for payment
thereof shall be the next preceding Euro-Dollar Business Day.  If the
date for any payment of principal is extended by operation of law or
otherwise, interest thereon shall be payable for such extended time.

                  (b) Unless the Administrative Agent shall have received notice
from the  Borrower  prior to the date on which any  payment  is due to the Banks
hereunder   that  the  Borrower  will  not  make  such  payment  in  full,   the
Administrative  Agent may assume that the Borrower has made such payment in full
to the Administrative  Agent on such date and the  Administrative  Agent may, in
reliance upon such assumption,  cause to be distributed to each Bank on such due
date an amount equal to the amount

                                       29





then due such Bank.  If and to the extent  that the  Borrower  shall not have so
made such payment,  each Bank shall repay to the Administrative  Agent forthwith
on demand such amount  distributed to such Bank together with interest  thereon,
for each day from the date such  amount is  distributed  to such Bank  until the
date such Bank repays such amount to the  Administrative  Agent,  at the Federal
Funds Rate.

                  SECTION  1.12.  Funding  Losses.  If the  Borrower  makes  any
payment of principal  with respect to any  Euro-Dollar  Loan or any Euro- Dollar
Loan is converted  (pursuant to Article 2, 6 or 8 or otherwise) on any day other
than the last day of an Interest Period applicable  thereto,  or the last day of
an applicable  period fixed pursuant to Section 2.5(c), or if the Borrower fails
to borrow or prepay any Euro-  Dollar  Loans after  notice has been given to any
Bank in  accordance  with  Section  2.2(a),  2.4 or  2.10,  the  Borrower  shall
reimburse  each Bank  within 15 days  after  demand  for any  resulting  loss or
expense  incurred  by it (or by an existing or  prospective  Participant  in the
related Loan),  including  (without  limitation) any loss incurred in obtaining,
liquidating  or employing  deposits from third  parties,  but excluding  loss of
margin for the period after any such payment or  conversion or failure to borrow
or  prepay,  provided  that such Bank  shall have  delivered  to the  Borrower a
certificate as to the amount of such loss or expense, which certificate shall be
conclusive in the absence of manifest error.

                  SECTION 1.13. Computation of Interest and Fees. Interest based
on the Prime Rate and commitment  fees hereunder  shall be computed on the basis
of a year of 365  days  (or 366 days in a leap  year)  and  paid for the  actual
number of days elapsed (including the first day but excluding the last day). All
other interest shall be computed on the basis of a year of 360 days and paid for
the actual  number of days elapsed  (including  the first day but  excluding the
last day).


                                    ARTICLE 2

                                   CONDITIONS

                  SECTION 2.1.  Closing.  The closing hereunder shall occur
upon satisfaction of the following conditions:

                  (a) the  Documentation  Agent shall have  received  all of the
following,  in form and substance satisfactory to the Documentation Agent and in
sufficient copies for each Bank:

                        (i) a duly  executed  Note for the  account of each Bank
         dated on or before the Closing Date  complying  with the  provisions of
         Section 2.3;

                       (ii) the articles or certificate of incorporation of each
         of the Borrower, the Parent Guarantor and the Shareholder Guarantors as
         in effect on the Closing  Date,  certified by the Secretary of State or
         equivalent official of the jurisdiction of incorporation of such Person
         as of a recent date and by the

                                       30





         Secretary or Assistant Secretary of such Person as of the Closing Date,
         and the  bylaws  of such  Person  as in  effect  on the  Closing  Date,
         certified by the Secretary or Assistant  Secretary of such Person as of
         the Closing Date;

                       (iii)  a  good  standing  certificate  for  each  of  the
         Borrower and the Parent  Guarantor  from the  Secretary of State of its
         state of  incorporation  and each state where the Borrower is qualified
         to do business as a foreign  corporation as of a recent date,  together
         with a bring-down  certificate by telex or telecopy,  dated the Closing
         Date;

                        (iv) copies of the resolutions of the board of directors
         of (x) the Borrower  approving and authorizing the execution,  delivery
         and  performance  by the Borrower of this  Agreement and the other Loan
         Documents to be delivered by it and  authorizing  the  borrowing of the
         Loans,  certified  as of  the  Closing  Date  by  the  Secretary  or an
         Assistant  Secretary  of the  Borrower,  and  (y)  each  of the  Parent
         Guarantor and the Shareholder  Guarantors approving and authorizing the
         execution,  delivery  and  performance  by  such  Person  of  all  Loan
         Documents to be  delivered  by it,  certified as of the Closing Date by
         the Secretary or an Assistant Secretary of such Person;

                        (v) a  certificate  of  the  Secretary  or an  Assistant
         Secretary  of each of the  Borrower,  the  Parent  Guarantor  and  each
         Shareholder  Guarantor  certifying the names and true signatures of its
         officers authorized to execute, deliver and perform, as applicable, all
         Loan Documents to be delivered by it hereunder;

                        (vi) a certificate  signed by a  Responsible  Officer of
         each of the Borrower and the Parent Guarantor,  dated as of the Closing
         Date,  stating that each of the conditions set forth in Sections 3.1(b)
         and (c) is satisfied as of such date;

                        (vii) a copy of each of the Common Collateral  Documents
         (other than the Notice of Amount of Secured Obligations,  the Notice of
         New Secured Party and the Security Agreement  Amendment),  certified as
         of the Closing Date by the  Secretary or an Assistant  Secretary of the
         Borrower;

                        (viii) written advice relating to such Lien and judgment
         searches  as either  Agent or the Common  Collateral  Agent  shall have
         requested  of  the  Parent   Guarantor  and  the  Borrower,   and  such
         termination  statements  or  other  documents  as may be  necessary  to
         release any Lien in favor of any third party not otherwise permitted by
         Section 5.17;

                         (ix)  evidence  (A)  that  all  filings,  recordations,
         registrations  and other actions necessary or, in the opinion of either
         Agent or the Common Collateral Agent,  desirable to perfect and protect
         a first  priority  (except for Permitted  Liens arising by operation of
         law) security interest in and Lien on the Common Collateral (other than

                                       31





         the Satellite and the proceeds of the FCC License and the Satellite) in
         favor of the Common  Collateral Agent have been duly effected or taken;
         (B) that each Lien created by the Common  Collateral  Documents in such
         Common  Collateral  constitutes  a  perfected  Lien on or in all right,
         title,  estate and interest of the Borrower or the Parent  Guarantor in
         such  Common  Collateral  prior and  superior  to all Liens  other than
         Permitted Liens arising by operation of law; and (C) that all necessary
         and  appropriate  consents to the creation and perfection of such Liens
         of  each  of the  parties  to the  Project  Documents  will  have  been
         obtained;

                           (x)  evidence  (A)  that all  filings,  recordations,
         registrations  and other actions necessary or, in the opinion of either
         Agent or the Common Collateral Agent,  desirable to perfect and protect
         a first priority  security  interest in and Lien on the proceeds of the
         FCC  License  have been  duly  effected  or  taken;  (B) that each Lien
         created by the Common  Collateral  Documents in the proceeds of the FCC
         License  constitutes a perfected Lien on or in all right, title, estate
         and  interest of the  Borrower or the Parent  Guarantor  in such Common
         Collateral  to the fullest  extent such a Lien may be legal,  valid and
         enforceable  under  applicable  law;  and (C)  that all  necessary  and
         appropriate  consents  to the  creation  of such  Liens  of each of the
         parties to the Project Documents has been obtained;

                           (xi) evidence (A) with respect to the Satellite, that
         all  filings,  recordations,  registrations  and other  actions  as are
         consistent  with  the  present   practices  of  third-party   creditors
         intending to create perfected security interests in satellites owned by
         U.S. persons launched from the United States have been duly effected or
         taken; (B) that each Lien created by the Common Collateral Documents in
         the Satellite  constitutes a perfected Lien on or in all right,  title,
         estate and  interest  of the  Borrower or the Parent  Guarantor  in the
         Satellite,  to the extent normally constituted by the present practices
         of  third-party   creditors  intending  to  create  perfected  security
         interests in satellites  owned by U.S. persons launched from the United
         States;  and (C) that all  necessary  and  appropriate  consents to the
         creation  and  perfection  of such Liens of each of the  parties to the
         Project Documents has been obtained;

                          (xii) evidence that the Common Collateral Agent or the
         Administrative Agent, as applicable, has been named as loss payee under
         all policies of casualty insurance (including,  without limitation, the
         Launch Insurance and the In-Orbit Insurance) and business  interruption
         insurance  required by Section 5.6, and as additional insured under all
         policies of liability insurance;

                         (xiii) the Notice of Amount of Secured  Obligations and
         the  Notice  of  New  Secured  Party,  duly  executed  by  each  of the
         signatories thereto;


                                       32





                          (xiv) an opinion of (w) Randy S. Segal, counsel to the
         Borrower and the Parent Guarantor, substantially in the form of Exhibit
         B-1 hereto, (x) Fisher, Wayland, Cooper, Leader & Zaragoza, special FCC
         counsel to the Borrower and the Parent Guarantor,  substantially in the
         form of Exhibit B-2 hereto, (y) counsel reasonably  satisfactory to the
         Agents  to  each   Shareholder   Guarantor,   in  form  and   substance
         satisfactory to the Documentation Agent, and (z) Davis Polk & Wardwell,
         special counsel to the Agents,  substantially  in the form of Exhibit C
         hereto;

                          (xv) a copy of (x)  the  financial  statements  of the
         Parent  Guarantor  referred  to  in  Section  4.10(a),  certified  by a
         Responsible  Officer  of the  Parent  Guarantor  and (y)  each  Project
         Document  which is in effect  (including  all  exhibits,  schedules and
         documents referred to therein or delivered  pursuant thereto,  if any),
         together with any amendments thereto;

                         (xvi)  a   Shareholder   Guaranty   executed   by  each
         Shareholder  Guarantor,  the Baron  Capital  Letter  of Credit  and the
         Escrow Letter  Agreement  dated June 28, 1996 among the  Administrative
         Agent, the Borrower and the Parent Guarantor and a Principal Subsidiary
         Guaranty executed by each Principal  Subsidiary (if any) other than the
         Borrower; and

                         (xvii)  all  documents  the  Documentation   Agent  may
         reasonably  request  relating to the  existence  of the  Borrower,  the
         Parent Guarantor or any Shareholder Guarantor,  the corporate authority
         for and the validity of this  Agreement,  the Notes or the  Shareholder
         Guaranties,  and any other  matters  relevant  hereto,  all in form and
         substance satisfactory to the Documentation Agent;

                  (b) the fact  that all  costs,  accrued  and  unpaid  fees and
expenses (including,  without limitation,  participation fees and legal fees and
expenses) to the extent then due and payable on the Closing Date by the Borrower
hereunder have been so paid; and

                  (c)  the fact that the FCC License is held by the Borrower
and is in full force and effect.

The Documentation  Agent shall promptly notify the Borrower and the Banks of the
Closing  Date,  and such notice shall be  conclusive  and binding on all parties
hereto.

                  SECTION 2.2.  Initial Borrowing.  The obligation of any Bank
to make a Loan on the occasion of the initial Borrowing is subject to
the satisfaction of the following conditions:

                  (a) the  Documentation  Agent shall have  received  all of the
following  on or  before  the  date of such  Borrowing,  in form  and  substance
satisfactory to the Documentation Agent and in sufficient copies for each Bank:


                                       33





                       (i) an appraisal by Ascent Communications Advisers, L.P.,
         dated as of a recent date,  showing that the  Satellite has an expected
         life of not less than eight  years and an  appraised  value of not less
         than $425,000,000;

                      (ii) In Orbit Test  Reports  (collectively,  the "IOT") on
         the Satellite prepared by Hughes Space and Communications,  Inc., dated
         as of May 10, 1995 and August 8, 1995, and each attachment to the Proof
         of Loss Statement;

                     (iii) a certificate signed by a Responsible  Officer of the
         Borrower,  dated as of the date of such  Borrowing,  stating  that such
         Person has  reviewed  the IOT and that based upon such  review and such
         other investigations of fact as such Person deems relevant, there is no
         basis for any claim  against any  insurance in respect of any damage to
         or the condition of the  Satellite  except as set forth in the Proof of
         Loss Statement;

                      (iv) a certificate signed by a Responsible  Officer of the
         Borrower,  dated as of the  date of such  Borrowing,  stating  that the
         Satellite is capable of providing the frequency and geographic coverage
         at the power levels for which it is designed  over (i) the  continental
         United States,  (ii) all areas within 200 miles of the shoreline of the
         continental United States,  (iii) the U.S. Virgin Islands,  (iv) Hawaii
         and (v) Alaska,  except that the  Satellite  is  operating  in a 5-beam
         configuration  with transmitting  power of 457,000 watts, and that as a
         result the Satellite's  capacity is expected to be reduced by an amount
         that will not affect its  ability  to  provide  the  telecommunications
         capacity assumed in the Information Memorandum; and

                       (v) a report from  Telesat  Canada dated the Closing Date
         as to the condition of the Satellite;  provided that the  Documentation
         Agent  acknowledges  report of Telesat Canada dated January 7, 1996, is
         satisfactory  as of such date with  respect  to the  matters  set forth
         therein.

                  (b)  the fact that the Closing Date shall have occurred on
or prior to July 12, 1996; and

                  (c) the fact that,  upon  application  of the  proceeds of the
initial Borrowing, no Bridge Notes or Interim Notes shall be outstanding.

                  SECTION 2.3.  All Borrowings.  The obligation of any Bank to
make a Loan on the occasion of any Borrowing is subject to the
satisfaction of the following conditions:

                  (a)  receipt by the Administrative Agent of a Notice of
Borrowing as required by Section 2.2(a);


                                       34





                  (b) the fact  that,  immediately  after  such  Borrowing,  the
aggregate  outstanding  principal  amount  of the  Loans  will  not  exceed  the
aggregate amount of the Commitments;

                  (c)  the fact that, immediately before and after such
Borrowing, no Default shall have occurred and be continuing;

                  (d) the fact that the  representations  and  warranties of the
Borrower and the Parent  Guarantor  contained in this  Agreement  and the Common
Collateral Documents shall be true on and as of the date of such Borrowing; and

                  (e) the fact that immediately before and after such Borrowing,
the Borrower  shall not be in  violation  of Section 3 of the Guaranty  Issuance
Agreement.

Each Borrowing  hereunder shall be deemed to be a representation and warranty by
the  Borrower and the Parent  Guarantor on the date of such  Borrowing as to the
facts specified in clauses (b) through (e) of this Section.


                                    ARTICLE 3

                         REPRESENTATIONS AND WARRANTIES

                  Each of the Borrower and the Parent  Guarantor  represents and
warrants  that,  except as set forth in the section  (if any) of the  Disclosure
Schedule corresponding to the Section heading below:

                  SECTION 3.1. Corporate Existence and Power. Each of the Parent
Guarantor,   the  Borrower,   and  each  of  its  Principal   Subsidiaries   and
Subsidiaries,  respectively,  (a) is a corporation  duly  incorporated,  validly
existing  and in  good  standing  under  the  laws  of the  jurisdiction  of its
incorporation;  (b) has the power and  authority  and all material  governmental
licenses,  authorizations,  consents  and  approvals  required  to  carry on its
business  as now  conducted;  (c) is duly  qualified  as a foreign  corporation,
licensed  and in good  standing  under the laws of each  jurisdiction  where its
ownership,  lease or  operation  of  property  or the  conduct  of its  business
requires such  qualification;  and (d) is in compliance with all Requirements of
Law  except,  in the case of  clauses  (c) and (d),  where the  failure to be so
qualified or in compliance  could not  reasonably be expected to have a Material
Adverse Effect.

                  SECTION 3.2. Corporate  Authorization;  No Contravention.  The
execution,  delivery and  performance  by each of the Parent  Guarantor  and its
Subsidiaries  of any  Loan  Document  to  which  it is a party  have  been  duly
authorized  by all  necessary  corporate  action  and do not and will  not:  (a)
contravene the terms of such Person's  certificate of  incorporation,  bylaws or
other  organization  document;  (b)  conflict  with or result  in any  breach or
contravention  of, or the creation of any Lien under, any indenture,  agreement,
lease,  instrument,   Contractual  Obligation,   injunction,  order,  decree  or
undertaking to which such

                                       35





Person is a party (other than Liens under the Common Collateral  Documents);  or
(c) violate any Requirement of Law.

                  SECTION 3.3. Government  Approvals.  All Government  Approvals
which are necessary under applicable laws and regulations in connection with the
grant of the Liens created by the Common Collateral  Documents and the validity,
enforceability  and  perfection  thereof and the exercise by the  Administrative
Agent or the Common Collateral Agent of its rights and remedies  thereunder have
been obtained.  All such Government Approvals heretofore required to be obtained
have been duly obtained,  were validly issued, are in full force and effect, are
not  subject to appeal and are held in the name of, or for the  benefit  of, the
appropriate Persons. There is no proceeding pending or, to the best knowledge of
the Borrower or the Parent Guarantor, threatened against the Parent Guarantor or
any of its  Subsidiaries,  or any property of the Parent Guarantor or any of its
Subsidiaries, which seeks, or may reasonably be expected, to rescind, terminate,
modify or suspend the FCC  License.  There has not occurred any event that would
make unlikely the delivery or issuance as anticipated of, and when and as needed
all such Government  Approvals.  No such Government Approval already obtained is
subject to any restriction,  condition, limitation or other provision that would
have a Material  Adverse Effect.  The information set forth in each  application
submitted  by the Parent  Guarantor,  the  Borrower  or any of their  respective
Subsidiaries in connection  with each such  Government  Approval is accurate and
complete in all material  respects  taken as a whole,  except for  statements or
omissions  which  could not  reasonably  be  expected  to affect  adversely  the
validity of such Government  Approvals.  No other material consent,  approval or
authorization of, or declaration or filing with, any other Person is required in
connection with the execution, delivery, performance, validity or enforceability
of this Agreement or any other Project Document.

                  SECTION 3.4.  Binding  Effect.  This  Agreement and each other
Loan  Document to which the Parent  Guarantor  or any of its  Subsidiaries  is a
party  constitute  the legal,  valid and  binding  obligations  of such  Person,
enforceable  against  such Person in  accordance  with their  respective  terms,
except as enforceability may be limited by applicable bankruptcy, insolvency, or
similar laws  affecting the  enforcement  of creditors'  rights  generally or by
equitable principles relating to enforceability.

                  SECTION 3.5. Litigation.  Except for matters arising after the
Effective Date which could not reasonably be expected to have a Material Adverse
Effect, there are no actions, suits, proceedings, claims or disputes pending, or
to the best  knowledge of the Parent  Guarantor or the  Borrower,  threatened or
contemplated  at law,  in equity,  in  arbitration  or before  any  Governmental
Authority,  against the Parent  Guarantor or any of its  Subsidiaries  or any of
their  respective  properties  which:  (a)  purport to affect or pertain to this
Agreement, or any Loan Document, or any of the transactions  contemplated hereby
or thereby; or (b) if determined adversely to the Parent Guarantor or any of its
Subsidiaries,  could  have a  Material  Adverse  Effect.  No  injunction,  writ,
temporary restraining order or any order of any nature has been issued

                                       36





by any court or other  Governmental  Authority  purporting to enjoin or restrain
the  execution,  delivery and  performance  of this  Agreement or any other Loan
Document,  or directing that the transactions provided for herein or therein not
be consummated as herein or therein provided.

                  SECTION 3.6. No Default. No Default or Event of Default exists
or would result from the incurring of Obligations by the Parent Guarantor or any
of its Subsidiaries under any other Loan Document.  Neither the Parent Guarantor
nor  any  of its  Subsidiaries  is in  default  under  or  with  respect  to any
Contractual  Obligation in any respect which,  individually or together with all
such defaults, could have a Material Adverse Effect.

                  SECTION 3.7.  ERISA Compliance.

                  (a) Section  4.7 of the  Disclosure  Schedule  lists all Plans
maintained  or  sponsored  by the Parent  Guarantor  or the Borrower or to which
either of them is obligated  to  contribute,  and  separately  identifies  Plans
intended to be Qualified Plans and Multiemployer Plans. All written descriptions
thereof  provided to the Agents are true and complete in all material  respects.
Each  Plan  is in  compliance  in all  material  respects  with  the  applicable
provisions  of ERISA,  the Code and other  Federal or state law,  including  all
requirements  under the Code or ERISA for  filing  reports  (which  are true and
correct in all material  respects as of the date filed),  and benefits have been
paid in accordance with the provisions of the Plan. Each Qualified Plan has been
determined by the IRS to qualify under Section 401 of the Code,  and to the best
knowledge of the Parent  Guarantor and the Borrower  nothing has occurred  which
would cause the loss of such qualification.

                  (b) There is no outstanding  liability under Title IV of ERISA
with respect to any Plan maintained or sponsored by any member of the Controlled
Group (as to which the Parent  Guarantor  or the  Borrower is or may be liable),
nor with  respect  to any Plan to  which  any  member  of the  Controlled  Group
contributes or is obligated to contribute  (wherein the Parent  Guarantor or the
Borrower is or may be liable).  No Plan  maintained  or  sponsored by the Parent
Guarantor or the Borrower  provides medical or other welfare benefits or extends
coverage   relating  to  such  benefits  beyond  the  date  of  a  participant's
termination of employment with the Parent  Guarantor or Borrower,  except to the
extent  required  by  Section  4980B of the Code and at the sole  expense of the
participant  or  the  beneficiary  of the  participant  to  the  fullest  extent
permissible under such Section of the Code. Each of the Parent Guarantor and the
Borrower has complied in all material  respects with the notice and continuation
coverage requirements of Section 4980B of the Code.

                  (c) No ERISA Event has occurred or is  reasonably  expected to
occur with respect to any Plan  maintained or sponsored by the Parent  Guarantor
or the Borrower or to which the Parent Guarantor or the Borrower is obligated to
contribute.  There  are no  pending  or,  to the best  knowledge  of the  Parent
Guarantor and the Borrower, threatened claims, actions or lawsuits, other

                                       37





than routine claims for benefits in the usual and ordinary  course,  asserted or
instituted  against (i) any Plan maintained or sponsored by the Parent Guarantor
or the  Borrower or its  assets,  (ii) any member of the  Controlled  Group with
respect to any Qualified Plan of the Parent Guarantor or the Borrower,  or (iii)
any  fiduciary  with  respect to any Plan for which the Parent  Guarantor or the
Borrower  may  be  directly  or  indirectly  liable,   through   indemnification
obligations  or  otherwise.  Neither the Parent  Guarantor  nor the Borrower has
incurred  or  reasonably  expects to incur (i) any  liability  (and no event has
occurred  which,  with the giving of notice under  Section 4219 of ERISA,  would
result  in such  liability)  under  Section  4201 of  ERISA  with  respect  to a
Multiemployer  Plan or (ii) any  liability  under Title IV of ERISA  (other than
premiums due and not  delinquent  under Section 4007 of ERISA) with respect to a
Plan. Neither the Parent Guarantor nor the Borrower has transferred any Unfunded
Pension  Liability  outside of the  Controlled  Group or otherwise  engaged in a
transaction that could be subject to Section 4069 or 4212(c) of ERISA.

                  (d) Neither the Parent Guarantor nor the Borrower has engaged,
directly or indirectly,  in a non-exempt  prohibited  transaction (as defined in
Section 4975 of the Code or Section 406 of ERISA) in  connection  with any Plan,
which transaction could have a Material Adverse Effect.

                  SECTION 3.8. Title to Property.  Each of the Parent Guarantor,
the Borrower, each of its Principal Subsidiaries and Subsidiaries, respectively,
and the Second  Satellite  Subsidiary  (if any) has good  record and  marketable
title in fee simple to or valid leasehold interests in all real property used in
its business,  except for such defects in title as could not, individually or in
the aggregate,  have a Material  Adverse Effect.  Such real property is free and
clear of all Liens or rights of others, except Permitted Liens.

                  SECTION  3.9.  Taxes.  The  Parent  Guarantor,   each  of  its
Principal Subsidiaries,  the Borrower, its Subsidiaries and the Second Satellite
Subsidiary  (if any) have filed all Federal and other  material  tax returns and
reports required to be filed and have paid all Federal and other material taxes,
assessments,  fees and other governmental charges levied or imposed upon them or
their properties,  income or assets otherwise due and payable except those which
are being  contested  in good  faith by  appropriate  proceedings  and for which
adequate  reserves have been  provided in accordance  with GAAP and no Notice of
Lien has been filed or recorded. There is no proposed tax assessment against the
Parent Guarantor or any of its Subsidiaries  which would, if the assessment were
made, have a Material Adverse Effect.

                  SECTION 3.10.  Financial Condition.

                  (a) The audited consolidated financial statements of financial
position of the Parent Guarantor and its  Subsidiaries  dated December 31, 1995,
and the related consolidated  statements of loss,  stockholders' equity and cash
flows for the  fiscal  year  ended on that date and the  unaudited  consolidated
financial statements of financial condition of the Parent Guarantor and its

                                       38





Subsidiaries  dated March 31, 1996:  (i) were prepared in  accordance  with GAAP
consistently applied throughout the periods covered thereby, except as otherwise
expressly  noted  therein and except for the absence of footnote  disclosure  in
such statements for the period ended March 31, 1996; (ii) fairly present, in all
material  respects,  the  financial  condition of the Parent  Guarantor  and its
Subsidiaries  as of the dates thereof and results of  operations  for the period
covered  thereby;  and (iii) solely in the case of the statements for the period
ended December 31, 1995, show all material  Indebtedness and other  liabilities,
direct or contingent,  of such Persons and their consolidated Subsidiaries as of
the date thereof (including liabilities for taxes and material commitments).

                  (b)  Since December 31, 1995, there has been no Material
Adverse Effect.

                  SECTION 3.11.  Environmental  Matters.  The  operations of the
Parent  Guarantor and each of its Subsidiaries  comply in all material  respects
with all  Environmental  Laws. The Parent Guarantor and each of its Subsidiaries
have obtained all licenses,  permits,  authorizations and registrations required
under  any  Environmental  Law  ("Environmental   Permits")  necessary  for  its
operations to comply in all material respects with  Environmental  Laws, and all
such  Environmental  Permits  are in full  force  and  effect,  and  the  Parent
Guarantor and each of its Subsidiaries are in material compliance with all terms
and conditions of such Environmental Permits. None of the Parent Guarantor,  any
of its  Subsidiaries  or any of their present or, to the knowledge of the Parent
Guarantor  and the  Borrower,  past  property  or  operations  is subject to any
outstanding  written order from or agreement with any Governmental  Authority or
other  Person,  nor  subject  to  any  judicial  or  administrative  proceeding,
respecting any Environmental  Law,  Environmental  Claim or Hazardous  Material.
There  are  no  conditions  or   circumstances   which  may  give  rise  to  any
Environmental  Claim arising from the operations of the Parent  Guarantor or its
Subsidiaries,  including  Environmental Claims associated with any operations of
the Parent Guarantor or its Subsidiaries,  with a potential  liability in excess
of  $5,000,000  in  the  aggregate.  Without  limiting  the  generality  of  the
foregoing,  the Parent Guarantor and its Subsidiaries  have met all notification
requirements under Title III of the Superfund Amendments and Reauthorization Act
of 1986 or any other Environmental Law.

                  SECTION  3.12.   Regulated   Entities.   None  of  the  Parent
Guarantor,  any Person  controlling  the  Parent  Guarantor,  or any  Subsidiary
thereof,  is (a) an  "Investment  Company"  within the meaning of the Investment
Company  Act of 1940;  or (b)  subject to  regulation  under the Public  Utility
Holding Company Act of 1935, the Federal Power Act, the Interstate Commerce Act,
any  state  public  utilities  code or any other  Federal  or state  statute  or
regulation limiting its ability to incur Indebtedness.

                  SECTION 3.13.  Subsidiaries.  As of the Closing Date, the
Borrower does not have any Subsidiaries and has no equity investments in
any other corporation or entity.

                                       39





                  SECTION 3.14.  Insurance.  The  properties of the Borrower and
its  Subsidiaries  are insured with  financially  sound and reputable  insurance
companies,  in such amounts, with such deductibles and covering such risks as is
customarily  carried on by companies  engaged in similar  businesses  and owning
similar properties in localities where the Borrower or such Subsidiary operates,
in each case in such amounts and with such terms as required by Section 5.6.

                  SECTION  3.15.  Project  Compliance.   The  Project  has  been
constructed  in  accordance  with the  Project  Documents  and  complies  in all
material respects with all covenants, conditions,  restrictions and reservations
in the Government  Approvals and Project Documents applicable thereto except for
failures which could not reasonably be expected to affect adversely the validity
of such Government Approvals.

                  SECTION 3.16. Business. The Borrower and its Subsidiaries have
not conducted any business other than any business  associated  with  financing,
designing,  constructing,  owning,  operating  and  maintaining  the Project and
leasing  satellite  capacity.  Neither the  business nor the  properties  of the
Borrower and its Subsidiaries are or have been affected by any fire,  explosion,
accident,  strike,  lockout  or  other  labor  dispute,  drought,  storm,  hail,
earthquake,  embargo,  act of  God or of the  public  enemy  or  other  casualty
(whether or not covered by insurance) which has had a Material Adverse Effect.

                  SECTION  3.17.  Collateral;  Property.  All  contracts and all
property now owned by the Borrower and its Subsidiaries are held by such Persons
free  and  clear  of all  Liens  other  than  Permitted  Liens.  Subject  to the
restrictions on the transferability of the FCC License, each of the Borrower and
its  Subsidiaries  has good,  marketable  and  valid  title in and to all of the
Common  Collateral  now  owned by it,  in each  case free and clear of all Liens
other than Permitted Liens.

                  SECTION  3.18.  Common   Collateral.   The  Common  Collateral
Documents  create in favor of the  Common  Collateral  Agent,  for the equal and
ratable (except as expressly  provided therein) benefit of the Common Collateral
Parties,  legal,  valid  and  enforceable  Liens  on or in  all  of  the  Common
Collateral  to the extent that such Liens may legally be given and be  effective
and  enforceable.  All filings,  recordations,  registrations  and other actions
necessary to perfect such Liens have been duly effected, and, to the extent that
such Liens may  legally be given and be  effective  and  enforceable,  each Lien
created by the Common Collateral Documents constitutes a perfected Lien on or in
all right,  title,  estate and interest of each of the Parent  Guarantor and its
Subsidiaries and the Borrower and its Subsidiaries, as applicable, in the Common
Collateral  covered  thereby,  prior  and  superior  to all other  Liens  except
Permitted  Liens arising by operation of law, and all necessary and  appropriate
consents to the creation and  perfection of such Liens of each of the parties to
the Project Documents have been obtained.

                  SECTION 3.19.  Sufficiency of Project Documents.  The
Project Documents (and any exhibits or documents referred to therein)

                                       40





which have been executed and delivered  constitute all  agreements  required for
the  acquisition,  construction  and  completion  of  the  Project  when  and as
contemplated  by the Project  Documents and the  Information  Memorandum and all
arrangements  to which the Parent  Guarantor or the Borrower is a party that may
affect the  financial  condition,  business or operations of the Borrower or the
Project or the ability of the  Borrower  to observe and perform its  obligations
under the  Project  Documents  to which it is a party.  All  permits,  licenses,
trademarks,  patents or  agreements  with respect to the usage of  technology or
other property (other than those constituting  Government  Approvals referred to
in  Section  4.3)  that are  necessary  for the  acquisition,  construction  and
ownership of the Project  substantially as contemplated by the Project Documents
and the  Information  Memorandum  have been obtained,  are final and are in full
force and  effect.  There are no material  services,  materials  or  contractual
rights required for the  acquisition,  construction and ownership of the Project
other than those granted by, or to be provided to the Borrower  pursuant to, the
Project Documents.

                  SECTION 3.20. Disclosure. The information (including,  without
limitation,  the information in the Information Memorandum) furnished in writing
at or prior to the Closing  Date by the Parent  Guarantor or the Borrower to any
Agent  or  Bank  in  connection   with  this  Agreement  and  the   transactions
contemplated  hereby is true, complete and accurate in every material respect or
based on reasonable estimates on the date as of which such information is stated
or  certified  and is not  incomplete  by  omitting to state any  material  fact
necessary to make such information (taken as a whole) not misleading in light of
the circumstances under which such information was made. The pro forma financial
projections contained in the Information  Memorandum were made in good faith and
the  assumptions  on the basis of which  such  projections  were made were (when
made) and are (as of the date of this  Agreement)  reasonable.  There is no fact
known to the  Parent  Guarantor  or the  Borrower  on the date as of which  this
representation  and  warranty is made that has not been  disclosed in writing to
the Agent which could reasonably be expected to have a Material Adverse Effect.

                  SECTION 3.21.  Effectiveness of Project Documents. The Project
Documents have not been modified or amended in any respect,  and no provision or
condition  contained  therein has been waived,  since the Effective Date, except
with the express written consent of the Required Banks.

                  SECTION 4.22.  Launch  Insurance.  The Borrower  maintained in
full  force and  effect at all times from and  including  April 7, 1995  through
October 4, 1995,  with  responsible  insurance  carriers with a Best's rating of
A/VII or better (except for policies  underwritten by Lloyds of London),  launch
insurance  with  respect  to the  Satellite  in a  minimum  aggregate  amount of
$250,000,000  (the  "Launch  Insurance").   The  Agents  and  the  Banks  hereby
irrevocably  approve the  Mission  Risk  Guarantee  provided in Article 8 of the
Launch Services Contract in lieu of any other Launch Insurance.



                                       41






                                    ARTICLE 4

                                    COVENANTS

                  Each of the Borrower and the Parent  Guarantor agrees that, so
long as any Bank has any Commitment hereunder or any amount payable hereunder or
under any Note remains unpaid:

                  SECTION 4.1.  Information.  The Borrower will deliver to
each of the Banks:

                  (a) as soon as available, but not later than 90 days after the
end of each fiscal year of the Borrower and the Parent Guarantor,  respectively,
commencing  with the fiscal year ending December 31, 1996, a copy of the audited
consolidated and unaudited  consolidating balance sheets of the Borrower and the
Parent Guarantor as at the end of such year and the related audited consolidated
and unaudited consolidating statements of income,  stockholders' equity and cash
flows for such fiscal year,  setting forth in each case in comparative  form the
figures for the previous year, and accompanied by the opinion of Arthur Andersen
LLP or another  nationally-recognized  independent  public accounting firm which
report shall state that such consolidated  financial  statements present fairly,
in all material respects, the financial position, results of operations and cash
flows for the  periods  indicated  in  conformity  with GAAP  applied on a basis
consistent with prior years;

                  (b) as soon as available, but not later than 45 days after the
end of each of the first three fiscal quarters of each year, commencing with the
first  such  fiscal  quarter  to end after  the  Effective  Date,  a copy of the
unaudited  consolidated  and  consolidating  balance  sheets of the Borrower and
Parent Guarantor as of the end of such quarter and the related  consolidated and
consolidating statements of income,  stockholders' equity and cash flows for the
period  commencing  on the first day and ending on the last day of such quarter,
and certified by an appropriate Responsible Officer as fairly presenting, in all
material  respects,  in accordance with GAAP (except for the absence of footnote
disclosure),  the  financial  position  and the  results  of  operations  of the
Borrower and the Parent Guarantor;

                  (c) within 20 Business  Days after the end of any month during
any fiscal quarter in which the Leverage Ratio, determined as of the last day of
the immediately  preceding fiscal quarter, is greater than or equal to 5.0 to 1,
an unaudited  statement setting forth the number of Subscribers on the last date
of such month,  the Borrower's  gross and net revenue for such month,  operating
expenses for such month,  monthly churn and other  financial and operating  data
reasonably  requested  by  the  Administrative  Agent  at the  direction  of the
Required Banks; and

                  (d)  as  soon  as  available,   any  other  interim  financial
statements  of the Borrower  and its  Subsidiaries  reasonably  requested by the
Administrative Agent at the direction of the Required Banks.

                                       42





                  SECTION 4.2.  Certificates; Other Information.  The Borrower
will deliver to each of the Banks:

                  (a) concurrently with the delivery of the financial statements
referred to in Section 5.1(a) above, a certificate of the independent  certified
public accountants reporting on such financial statements stating that in making
the examination  necessary  therefor no knowledge was obtained of any Default or
Event of Default, except as specified in such certificate;

                  (b) concurrently with the delivery of the statements  referred
to in Section  5.1(c)  above,  a  certificate  of a  Responsible  Officer of the
Borrower  showing (i) the  operating  results  projected  for such period as set
forth in the Borrower's  most recent annual budget covering such period and (ii)
the number of Subscribers;

                  (c) concurrently with the delivery of the financial statements
referred to in Sections  5.1(a) or 5.1(b) above,  a certificate of a Responsible
Officer  of the  Borrower  (i)  stating  that,  to the  best of  such  officer's
knowledge,  the Borrower,  during such period,  has observed or performed all of
its covenants and other agreements,  and satisfied every condition  contained in
this  Agreement  to be  observed,  performed  or  satisfied by it, and that such
officer has obtained no  knowledge of any Default or Event of Default  except as
specified in such  certificate and (ii) when  applicable,  showing in detail the
calculations  supporting  such  statement  in respect of Sections  5.28 to 5.33,
inclusive;

                  (d) promptly  after the same are filed,  copies of (if, in the
case of reports to the FCC, such reports are material) all financial  statements
and  regular,  periodical  or special  reports  which the Borrower or the Parent
Guarantor may make to, or file with, the Securities and Exchange Commission, the
FCC or any successor or similar Governmental Authorities;

                  (e)   concurrently   with  the   delivery  of  any  notice  or
certification  to a  Shareholder  Guarantor  pursuant to the  Guaranty  Issuance
Agreement, a copy of such notice or certification;

                  (f) within 20 Business Days after the end of each  three-month
period set forth on the Release Date  Schedule,  a certificate  of a Responsible
Officer of the Borrower  setting forth (i) the number of  Subscribers  as of the
last day of such period, (ii) Net Revenues for such period and (iii) the maximum
ratio at any time  during  such period of total  Indebtedness  of the  Guarantor
Group to the number of Subscribers; and

                  (g) promptly,  such additional financial and other information
as the  Administrative  Agent, at the request of any Bank, may from time to time
reasonably request.

                  SECTION 4.3.  Notices.  The Borrower shall promptly notify
the Agents and each Bank of:

                                       43





                  (a) the occurrence of any Default or Event of Default,  and of
the occurrence or existence of any event or circumstance  that could  reasonably
be expected to become a Default or Event of Default;

                  (b) any (i) breach or non-performance of, or any default under
any  Contractual  Obligation  which could  reasonably be expected to result in a
Material Adverse Effect; or (ii) dispute, litigation, investigation,  proceeding
or suspension which may exist at any time between the Parent Guarantor or any of
its  Subsidiaries  and any  Governmental  Authority  and  which,  if  determined
adversely to the Parent Guarantor or any of its  Subsidiaries,  could reasonably
be expected to result in a Material Adverse Effect;

                  (c) the commencement  of, or any material  development in, any
litigation or proceeding affecting the Parent Guarantor or any Subsidiary (i) in
which the amount of damages  claimed is $5,000,000 (or its equivalent in another
currency or currencies) or more,  (ii) in which  injunctive or similar relief is
sought and which, if adversely determined, could have a Material Adverse Effect,
or (iii) in which  the  relief  sought  is an  injunction  or other  stay of the
performance  of any Loan Document or the  operations of the Parent  Guarantor or
any of its Subsidiaries;

                  (d) upon, but in no event later than ten days after,  becoming
aware of (i) any and all enforcement,  cleanup, removal or other governmental or
regulatory  actions  instituted,  completed  or  threatened  against  the Parent
Guarantor  or  any  Subsidiary  or  any  of  their  properties  pursuant  to any
applicable Environmental Laws, (ii) all other Environmental Claims, or (iii) any
environmental  or similar  condition  on any real  property  adjoining or in the
vicinity of the property of the Parent Guarantor or any of its Subsidiaries that
could reasonably be anticipated to cause such property or any part thereof to be
subject to any restrictions on the ownership, occupancy,  transferability or use
of such property under any Environmental Laws;

                  (e) any other  litigation or  proceeding  affecting the Parent
Guarantor  or any of its  Subsidiaries  which  the  Parent  Guarantor  would  be
required to report to the  Securities  and Exchange  Commission  pursuant to the
Securities  Exchange Act of 1934,  within four days after  reporting the same to
the Securities and Exchange Commission;

                  (f) any ERISA Event  affecting  the  Borrower or any member of
its Controlled Group (but in no event more than ten days after such ERISA Event)
together  with (i) a copy of any notice  with  respect to such ERISA Event filed
with the PBGC and (ii) any notice  delivered  by the PBGC to the Borrower or any
member or its Controlled Group with respect to such ERISA Event;

                  (g) any Material Adverse Effect  subsequent to the date of the
most recent audited financial  statements of the Borrower delivered to the Banks
pursuant to Section 5.1(a);


                                       44





                  (h)  any material change in accounting policies or financial
reporting practices;

                  (i) any  labor  controversy  resulting  in or  threatening  to
result in any strike, work stoppage, boycott, shutdown or other labor disruption
against or involving the Borrower or any Subsidiary;

                  (j)  any material revision of the Borrower's business plan;

                  (k)  the adoption of each capital expenditures budget by the
Borrower;

                  (l) any Event of Loss that could  reasonably  be  expected  to
result in Net Cash Proceeds requiring a mandatory prepayment pursuant to Section
2.4;

                  (m) the  delivery  of,  or  receipt  of,  any  notice of (i) a
reduction in coverage of any insurance  required to be maintained by Section 5.6
or otherwise  procured by the Borrower  covering  loss or damage to any material
property of the Borrower (other than a reduction in coverage or amount resulting
from a payment  thereunder) or (ii) the  cancellation or non-renewal of any such
insurance policy;

                  (n)  the occurrence of a Guarantor Event; and

                  (o)  the occurrence of the Release Date.

                  Each  notice  pursuant  to this  Section  shall  be  delivered
promptly after a Responsible Officer becomes aware of the subject matter of such
notice and shall be accompanied by a written statement by a Responsible  Officer
of the Borrower  setting  forth  details and  effective  date of the  occurrence
referred to therein and stating what action the  Borrower  proposes to take with
respect thereto.

                  SECTION 4.4.  Conduct of Business;  Preservation  of Corporate
Existence.  Each of the Parent Guarantor and the Borrower shall, and shall cause
each of its Principal Subsidiaries and Subsidiaries, respectively: (a) to engage
in business of the same  general type as now  conducted by the Parent  Guarantor
and its Subsidiaries;  (b) to preserve and maintain in full force and effect its
corporate   existence  and  good  standing  under  the  laws  of  its  State  or
jurisdiction  of  incorporation;  (c) to preserve and maintain in full force and
effect all rights, privileges, qualifications,  permits, licenses and franchises
necessary  or desirable in the normal  conduct of its  business;  (d) to use its
reasonable efforts, in the ordinary course and consistent with past practice, to
preserve its business organization and preserve the goodwill and business of the
customers,  suppliers and others having  business  relations with it; and (e) to
preserve  or renew all of its  registered  trademarks,  trade  names and service
marks, the non-preservation of which could have a Material Adverse Effect.

                  SECTION 4.5.  Maintenance of Property.  Each of the Borrower
and the Parent Guarantor shall maintain, and shall cause each of its

                                       45





Principal Subsidiaries and Subsidiaries, respectively, to maintain, and preserve
all its property  which is used or useful in its business in good working  order
and condition, ordinary wear and tear excepted.

                  SECTION 4.6.  Maintenance of Insurance.

                  (a) The Borrower shall procure at its own expense and maintain
in full  force and  effect at all  times on and  after the  Effective  Date with
responsible  insurance  carriers with a Best's rating of A/VII or better (except
for policies  underwritten  by Lloyds of London and companies  acceptable to the
Agents and the Required Banks), the following insurance:

                        (i)  Workers' Compensation Insurance:  Except as to
         exposures in those jurisdictions in which the state government is
         the sole source of such insurance, as required by applicable state
         laws including, without limitation, employer's liability insurance
         with the following limits: bodily injury by accident: $100,000
         each accident; bodily injury by disease: $100,000 each employee;
         and bodily injury by disease: $500,000 policy limit (the policies
         with respect to which shall include an all states' endorsement).

                        (ii) Commercial  General  Liability:  Against claims for
         personal injury (including bodily injury and death) and property damage
         in such amounts as are customarily  carried by companies of established
         repute  engaged  in the same or a  similar  business  but not to exceed
         $5,000,000 in the aggregate.  Such insurance shall provide coverage for
         products/completed operations, blanket contractual, explosion, collapse
         and  underground  coverage,  broad form  property  damage and  personal
         injury  insurance with $1,000,000 each occurrence,  $1,000,000  general
         aggregate  (other  than  products/completed   operations),   $1,000,000
         personal  and  advertising  limit,  and  $1,000,000  products/completed
         operations aggregate limit.

                       (iii) Business Automobile  Liability:  Against claims for
         personal injury (including bodily injury and death) and property damage
         covering all owned, leased,  non-owned and hired motor vehicles (to the
         extent  there are any  thereof),  with a $2,000,000  minimum  limit per
         occurrence  for combined  bodily injury and property  damage and in the
         aggregate where applicable.

                        (iv)  Business  Interruption  Insurance:  To the  extent
         reasonably  obtainable  on  customary  terms  and  conditions  and with
         customary  exclusions,  with  respect to any risk of loss in respect of
         which  the  Borrower  in its  judgment  does  not  then  have  adequate
         redundant  or  replacement  property  or assets  available  which would
         prevent  any  loss or  interruption  of any  cash  flow  if  such  loss
         occurred,  business  interruption  insurance with a $2,000,000  minimum
         limit per occurrence.

                         (v)  Property Damage Insurance:  (x) Property damage
         insurance on an "all risk" basis (with customary conditions and

                                       46





         exclusions)  including  coverage against damage or loss caused by earth
         movement and flood and providing coverage for the Project (the "Covered
         Property"),  in a minimum  aggregate  amount equal to the lesser of (1)
         the "full insurable  value" of the Covered Property and (2) 110% of all
         Obligations  and Vendor  Debt and (y) unless  both of the Agents  shall
         otherwise agree,  In-Orbit  Insurance.  For purposes of this clause (v)
         and  Section  5.6(b),  "full  insurable  value"  shall  mean  the  full
         replacement value of the Covered  Property,  including any improvements
         and equipment and supplies, without deduction for physical depreciation
         and/or  obsolescence;  all such  policies may have  deductibles  of not
         greater than $250,000,  except for earth movement  insurance which will
         have the lowest  deductible  as shall (in the opinion of the Agents) be
         available on  commercially  reasonable  terms in the  insurance  market
         place.  Such insurance  shall include an "agreed  amount"  clause.  For
         purposes of this clause (v),  "In-Orbit  Insurance" shall mean in-orbit
         insurance,  with  insurance  carriers  acceptable  to the Agents,  in a
         minimum  aggregate  amount  equal  to  $250,000,000  less  any  amounts
         recovered  in  respect  of the  events  set  forth in the Proof of Loss
         Statement and having  deductibles and other terms and conditions as are
         reasonably   available  in  the  market  at  reasonable  cost  and  are
         acceptable to the Agents.

                  (b)  All  policies  of  insurance  required  to be  maintained
pursuant to Sections  5.6(a)(iv)  and  5.6(a)(v)  or  otherwise  procured by the
Borrower covering loss or damage to any of the Borrower's property shall provide
that (i) there shall be no recourse against the Agents,  the Banks or the Common
Collateral for payment of premiums or other amounts with respect  thereto,  (ii)
to the extent available,  the insurer is required to provide the  Administrative
Agent with at least 30 days (or ten days, in the case of nonpayment of premiums)
prior written  notice of reduction in coverage or amount (other than a reduction
in coverage or amount  resulting  from a payment  thereunder),  cancellation  or
non-renewal of any policy and (iii) the proceeds of all policies  (other than in
respect  of  comprehensive   general   liability,   workers'   compensation  and
comprehensive   automobile   liability   insurance)  shall  be  payable  to  the
Administrative Agent or the Common Collateral Agent, as applicable,  pursuant to
standard  first  mortgagee  endorsement,  without  contribution,   substantially
equivalent to the New York standard mortgagee endorsement. If the Borrower fails
or may fail to timely file any proof of loss,  the  Administrative  Agent or the
Common  Collateral  Agent,  as  applicable,  shall  have  the  right to join the
Borrower  in  submitting  a proof of any loss in  excess of  $250,000.  All such
policies (other than in respect of workers' compensation insurance) shall insure
the interests of the Insured  Parties,  as their interest may appear,  and shall
further  provide,  to the extent such  insurance is available at a  commercially
reasonable rate, that payments shall be made thereunder regardless of any breach
or violation by the  Borrower of  warranties,  declarations  or  conditions  not
contained in such policies,  any action or inaction of the Borrower  (other than
nonpayment of premiums) or others, or any foreclosure relating to the Project or
any other  business  of the  Borrower or any change in  ownership  of all or any
portion of the Project or any other  business of the Borrower.  Each such policy
shall (i)

                                       47





except in the case of insurance  required to be maintained  pursuant to Sections
5.6(a)(iv)  and 5.6(a)(v),  waive any right of subrogation  against the Banks or
Common Collateral Parties (and their respective officers, employees and agents),
(ii)  except in the case of  insurance  required  to be  maintained  pursuant to
Sections  5.6(a)(iv) and 5.6(a)(v),  include a severability of interest or cross
liability clause,  (iii) provide that the insurance be primary and not excess of
or contributory to any insurance or  self-insurance  maintained by the Borrower,
the Agents or the Banks,  (iv)  contain a breach of warranty  clause in favor of
the  Agents,  the  Banks,  the  Common  Collateral  Parties,  and/or  the Common
Collateral  Agent,  as  applicable,  and (v)  except  in the  case  of  workers'
compensation insurance,  name the Insured Parties as their interests may appear,
as additional insureds or loss payees.

                  (c) The Borrower  shall deliver to the  Administrative  Agent,
within 30 days after the close of each fiscal year,  commencing  with the fiscal
year ending December 31, 1996, a certificate of Marsh & McLennan,  International
Space Brokers, Inc., Metro/Risk,  Inc. or other recognized independent insurance
brokers,  reasonably  acceptable to the Required Banks,  (i) confirming that all
insurance  policies  required  pursuant to this  Section 5.6 are in force on the
date thereof,  (ii) confirming the names of the companies issuing such policies,
(iii) confirming the amounts and expiration date or dates of such policies, (iv)
including  certificates  evidencing  such policies marked "premium paid" for the
prior  year  and  (v)  stating  that  in  such   broker's   opinion   after  due
investigation,  such policies substantially comply with the requirements of this
Section 5.6.

                  (d) In the event the  Borrower  fails to take out or maintain,
or fails to cause to be taken out or  maintained,  the full  insurance  coverage
required by this Section 5.6, the  Administrative  Agent (upon the  direction of
the  Required  Banks),  upon 30 days' prior  notice  (unless the  aforementioned
insurance would lapse within such period,  in which event notice should be given
as soon as reasonably  possible) to the Borrower of any such  failure,  may (but
shall not be obligated  to) take out the required  policies of insurance and pay
the premiums on the same. All amounts so advanced therefor by the Administrative
Agent shall be  immediately  reimbursed  by the  Borrower to the  Administrative
Agent,  and the Borrower shall forthwith pay such amounts to the  Administrative
Agent,  together with interest  thereon at the sum of 2% plus the rate otherwise
applicable to Base Rate Loans for each day until paid.

                  (e) The  Administrative  Agent shall promptly notify each Bank
of each written  notice  received by it with respect to the  cancellation  of or
material adverse change in any insurance policy required to be maintained by the
Borrower pursuant to this Section 5.6.

                  SECTION 4.7.  Payment of Obligations.  Each of the Parent
Guarantor and the Borrower shall, and shall cause each of its Principal
Subsidiaries and Subsidiaries, respectively, to, pay and discharge as
the same shall become due and payable, all its obligations and liabilities,
including:  (a) all tax liabilities, assessments and governmental charges or

                                       48





levies upon it or its properties or assets,  unless the same are being contested
in good faith by  appropriate  proceedings  and adequate  reserves in accordance
with GAAP are being  maintained by such Person;  (b) all lawful claims which, if
unpaid,  might by law become a Lien upon its  property  (excluding  claims being
contested in good faith by the Borrower,  and for which  adequate  reserves have
been made or as to which the corresponding liens have been bonded);  and (c) all
Indebtedness  as and when  due and  payable  but  subject  to any  subordination
provisions   contained  in  any   instrument   or  agreement   evidencing   such
Indebtedness.

                  SECTION  4.8.   Compliance  with  Laws.  Each  of  the  Parent
Guarantor and the Borrower  shall comply,  and shall cause each of its Principal
Subsidiaries and Subsidiaries, respectively, to comply, in all material respects
with all Requirements of Law of any Governmental  Authority having  jurisdiction
over it or its  business  (including  the Federal Fair Labor  Standards  Act and
ERISA), except such as may be contested in good faith or as to which a bona fide
dispute may exist.

                  SECTION  4.9.  Inspection  of Property  and Books and Records.
Each of the Parent  Guarantor and the Borrower shall  maintain,  and shall cause
each of its Principal Subsidiaries and Subsidiaries,  respectively, to maintain,
proper books of record and account,  in which full,  true and correct entries in
conformity  with  GAAP  consistently  applied  shall  be made  of all  financial
transactions  and  matters  involving  the  assets  and  business  of the Parent
Guarantor and the Borrower and such Principal  Subsidiaries.  Each of the Parent
Guarantor  and the Borrower  will permit,  and will cause each of its  Principal
Subsidiaries and Subsidiaries,  respectively, to permit,  representatives of any
Agent or Bank to  visit  and  inspect  any of its  properties,  to  examine  its
corporate,  financial and operating records and make copies thereof or abstracts
therefrom, and to discuss its affairs, finances and accounts with its directors,
officers,  employees and independent public accountants at such reasonable times
during normal  business  hours and as often as may be reasonably  desired,  upon
reasonable  advance notice to the Parent Guarantor or the Borrower,  as the case
may be; provided that when an Event of Default exists  representatives  from the
United States  offices of any Agent or Bank may visit and inspect at the expense
of the Borrower such  properties at any time during  business  hours and without
advance notice.  The Borrower shall reimburse the Agents and the Banks for their
reasonable  expenses incurred in conducting such visits and examinations when an
Event of Default exists.

                  SECTION 4.10.  Environmental Laws.

                  (a) Each of the Parent  Guarantor and the Borrower shall,  and
shall cause each of its  Subsidiaries  to,  conduct its  operations and keep and
maintain its property in compliance with all Environmental Laws.

                  (b) Upon  written  request of any Agent or Bank,  the Borrower
shall  submit and cause  each of its  Subsidiaries  to submit,  to such Agent or
Bank, at the Borrower's sole cost and expense at reasonable intervals, a

                                       49





report  providing  an update of the status of and any  environmental,  health or
safety  compliance  obligation,  remedial  obligation or liability,  that could,
individually or in the aggregate, result in liability in excess of $5,000,000.

                  SECTION  4.11.  Use of Proceeds.  The  Borrower  shall use the
proceeds of the Loans only for general  corporate  purposes,  including  capital
expenditures and the refinancing of Vendor Debt, Bridge Notes and Interim Notes.
No portion of the Loans will be used,  directly or indirectly,  for the purpose,
whether  immediate,  incidental  or ultimate,  of buying or carrying any "margin
stock" within the meaning of Regulation U. No proceeds of any Loans will be used
to acquire any security in any transaction  which is subject to Section 13 or 14
of the Securities Exchange Act of 1934, as amended.

                  SECTION 4.12. Common Collateral Documents and Guaranties.  (a)
If at any time and from  time to time the  Borrower  or any of its  Subsidiaries
grants a security  interest in any Common  Collateral or collateral which should
be Common  Collateral  to any Common  Collateral  Party,  such Person shall also
execute and deliver such Common  Collateral  Documents as the Common  Collateral
Agent  may  request  having  terms and  conditions  satisfactory  to the  Common
Collateral Agent granting to the Common Collateral Agent for the ratable benefit
of the Common  Collateral  Parties a security  interest in such  collateral on a
pari passu basis among the Common Collateral Parties.

                  (b) If at any time and from time to time  either of the Parent
Guarantor or the Borrower or any of its Principal  Subsidiaries or Subsidiaries,
respectively,  executes  any Guaranty in favor of any Common  Collateral  Party,
such  Person  shall  also  execute  and  deliver  a  Guaranty  having  terms and
conditions  satisfactory to the Common  Collateral  Agent in favor of the Common
Collateral Agent for the ratable benefit of the Common Collateral Parties.

                  (c) Except to the extent that any lien on,  security  interest
or other  right in, or pledge or other  encumbrance  of the FCC  License  or any
other Government Approval may not be legal, valid, enforceable or effective, the
Borrower  shall at all times  ensure  that (i) the Common  Collateral  Documents
executed and delivered  from time to time pursuant to this  Agreement  create in
favor of the Common  Collateral  Agent, for the equal and ratable benefit of the
Common  Collateral  Parties,  legal,  valid and  enforceable  Liens on or in all
Common  Collateral (or in the case of Liens on the Satellite,  as are consistent
with present  practices of third-party  creditors  intending to create perfected
security  interests in satellites owned by U.S. persons launched from the United
States);  (ii)  all  filings,  recordations,  registrations  and  other  actions
necessary or  desirable to perfect the Liens  created or purported to be created
by the Common  Collateral  Documents  have been duly  effected;  (iii) each Lien
created by the Common Collateral Documents constitutes a perfected Lien on or in
all right,  title,  estate and interest of the Borrower,  as applicable,  in the
Common  Collateral,  prior and superior to all Liens other than Permitted  Liens
arising by operation of law; and (iv) all necessary and appropriate consents to

                                       50





the creation and  perfection  of the Liens created or purported to be created by
the Common Collateral Documents have been obtained.

                  SECTION 4.13.  No Subsidiaries.  The Borrower shall not have
any Subsidiaries or equity investments in any other corporation or
entity.

                  SECTION 4.14. FCC Approval. The Borrower shall take any action
that the Administrative Agent may reasonably request in order to obtain from the
FCC  such   approval   (other  than  relief  from  the  FCC's  alien   ownership
restrictions)  as may be  necessary to enable the  Administrative  Agent and the
Common  Collateral  Agent to  exercise  and enjoy the full  rights and  benefits
granted to the Administrative Agent or the Common Collateral Agent by the Common
Collateral Documents and each other agreement, instrument and document delivered
to the  Administrative  Agent  or the  Common  Collateral  Agent  in  connection
therewith. The Borrower shall, without limitation, also use diligent efforts, at
the  expense  of the  Borrower,  (a) to assist the  Administrative  Agent or the
Common  Collateral  Agent in  obtaining  approval  of the FCC for any  action or
transaction  contemplated  by  the  Borrower's  business  plan  included  in the
Information  Memorandum  for which such approval is or shall be required by law,
and (b) upon request of the Administrative Agent or the Common Collateral Agent,
to prepare, sign and file with the FCC the assignor's or transferor's portion of
any application or applications  for consent to the assignment of any license or
transfer  or  control  necessary  or  appropriate  under  the  FCC's  rules  and
regulations  for  approval  of  any  sale  or  sales  of any  Collateral  or any
assumption by the Administrative  Agent or the Common Collateral Agent of voting
rights  relating  thereto  effected in  accordance  with the terms of the Common
Collateral Documents.

                  SECTION 4.15. Government Approvals.  The Borrower shall comply
with the terms of and maintain in full force and effect the FCC License, and all
amendments thereto, and shall obtain,  maintain and comply with the terms of all
other  Government  Approvals  which  are  necessary  under  applicable  laws and
regulations in connection  with (a) the due execution,  delivery and performance
by the Borrower or any of its Subsidiaries of its obligations,  and the exercise
from time to time of its rights, under the Project Documents then in effect, and
(b) the  operation of the Satellite and related  equipment.  No such  Government
Approval  shall be subject to any  restriction,  condition,  limitation or other
provision that would have a Material Adverse Effect.

                  SECTION 4.16.  Further Assurances.

                  (a) Each of the Borrower and the Parent Guarantor shall ensure
that all written information, exhibits and reports furnished to the Banks do not
and will not contain any untrue statement of a material fact and do not and will
not omit to state any material fact or any fact necessary to make the statements
contained  therein not misleading in light of the  circumstances  in which made,
and will promptly disclose to the Agents and the Banks and correct any defect or
error  that  may  be  discovered  therein  or in  any  Loan  Document  or in the
execution, acknowledgement or recordation thereof.


                                       51






                  (b) Promptly upon written request by the Administrative  Agent
or  the  Required  Banks,  the  Borrower  shall  (and  shall  cause  any  of its
Subsidiaries to) do, execute,  acknowledge,  deliver, record,  re-record,  file,
re-file,  register  and  re-register,  any and all  such  further  acts,  deeds,
conveyances, security agreements, mortgages, assignments, estoppel certificates,
financing statements and continuations thereof, termination statements,  notices
of assignment, transfers, certificates,  assurances and other instruments as the
Administrative  Agent or such Banks may reasonably  require from time to time in
order (i) to carry out more  effectively  the purposes of this  Agreement or any
other Loan  Document,  (ii) to subject to the Liens created by any of the Common
Collateral  Documents any of the properties,  rights or interests covered by any
of the Common Collateral Documents,  (iii) to perfect and maintain the validity,
effectiveness  and priority of any of the Common  Collateral  Documents  and the
Liens intended to be created thereby, and (iv) to better assure,  convey, grant,
assign, transfer,  preserve, protect and confirm to the Administrative Agent and
Banks the rights granted or now or hereafter intended to be granted to the Banks
under any Loan  Document or under any other  instrument  executed in  connection
therewith.

                  SECTION  4.17.   Limitation  on  Liens.   Neither  the  Parent
Guarantor nor the Borrower shall,  nor shall it permit any members of the Parent
Guarantor  Group to,  directly or indirectly,  make,  create,  incur,  assume or
suffer to exist any Lien upon or with  respect  to any part of its  property  or
assets,  whether now owned or  hereafter  acquired,  or offer or agree to do so,
other than the following ("Permitted Liens"):

                  (a)  any Lien in favor of the Administrative Agent created
under any Loan Document;

                  (b) Liens for taxes,  fees,  assessments or other governmental
charges which are not delinquent or remain payable  without  penalty,  or to the
extent that  non-payment  thereof is permitted by Section 5.7,  provided that no
Notice of Lien has been filed or recorded;

                  (c)   carriers',   warehousemen's,   mechanics',   landlords',
materialmen's, repairmen's or other similar Liens arising in the ordinary course
of business  which do not secure  Indebtedness  and are not delinquent or remain
payable without penalty;

                  (d)  Liens  (other  than any Lien  imposed  by  ERISA)  on the
property of any member of the Parent  Guarantor  Group  incurred,  or pledges or
deposits  required,  in connection  with  workmen's  compensation,  unemployment
insurance and other social security legislation;

                  (e)  Liens  on the  property  of  any  member  of  the  Parent
Guarantor  Group securing (i) the performance of bids,  trade  contracts  (other
than for borrowed money), leases, statutory obligations, and (ii) obligations on
surety and appeal bonds, and (iii) other obligations of a like nature incurred

                                       52





in the ordinary  course of business which do not secure  Indebtedness,  provided
that all such Liens in the aggregate could not cause a Material Adverse Effect;

                  (f) easements,  rights-of-way,  restrictions and other similar
encumbrances  incurred  in  the  ordinary  course  of  business  which,  in  the
aggregate,  are  not  substantial  in  amount,  and  which  do not  in any  case
materially  detract from the value of the property  subject thereto or interfere
with the ordinary conduct of the businesses of the Parent Guarantor Group;

                  (g) Liens on any asset which is the subject of a capital lease
securing  Indebtedness  incurred or assumed for the purpose of financing  all or
any  part of the cost of  acquiring  such  asset,  provided  that (x) such  Lien
attaches  concurrently with or within 30 days after the acquisition thereof, and
(y) the sum of the aggregate  principal amount of such  Indebtedness  secured by
such Liens shall not exceed $15,000,000;

                  (h)  Liens  on  any  Common  Collateral  in  favor  of  Common
Collateral  Parties;  provided  that such Liens  equally and ratably  secure the
Obligations  on a pari passu basis,  except as otherwise  provided in the Common
Collateral Documents;

                  (i) Liens on contract rights under subscriber equipment leases
sold,  pledged or otherwise  transferred  pursuant to any bona fide financing of
such leases; and

                  (j)  purchase  money  security   interests   provided  for  in
agreements in existence on the Effective  Date in favor of (A) Northern  Telecom
Finance Corporation and (B) Trimble Navigation Limited, in each case on property
acquired  by  the  Borrower  in  the  ordinary   course  of  business   securing
Indebtedness incurred or assumed for the purpose of financing all or part of the
cost of acquiring such asset, provided that (x) such Liens attached concurrently
with or within 30 days after the acquisition  thereof,  (y) the aggregate amount
of  Indebtedness  secured by such  Liens in favor of  Northern  Telecom  Finance
Corporation  shall  not  exceed  $7,500,000  and (z)  the  aggregate  amount  of
Indebtedness  secured by such Liens in favor of Trimble Navigation Limited shall
not exceed $1,730,000.

                  SECTION  4.18.  Disposition  of  Assets,   Consolidations  and
Mergers.  Neither the Parent  Guarantor  nor the  Borrower  shall,  nor shall it
permit any member of the Parent Guarantor Group to, directly or indirectly,  (i)
sell, assign, lease, convey, transfer or otherwise dispose of (whether in one or
a series of  transactions)  any of its assets,  business or property  (including
accounts  and  notes  receivable  (with  or  without   recourse)  and  equipment
sale-leaseback transactions) or (ii) merge or consolidate with any other Person,
or enter into any agreement to do any of the foregoing  described in clauses (i)
or (ii) except,  so long as if  immediately  after  giving  effect  thereto,  no
Default or Event of Default  would exist (each of the  following,  a  "Permitted
Disposition"):


                                       53





                  (a) sales,  transfers,  or other dispositions of inventory, or
used,  worn-out  or surplus  property,  or  property  of no  further  use to the
Project, all in the ordinary course of business;

                  (b) sales,  transfers,  or other  dispositions of equipment in
the ordinary  course of business to the extent that such  equipment is exchanged
for credit  against the purchase price of similar  replacement  equipment or the
proceeds of such sale are reasonably  promptly  applied to the purchase price of
such replacement equipment;

                  (c) sales,  transfers, or other dispositions of communications
services, capacity or equipment pursuant to the customer contracts providing for
the sale of  communications  services,  capacity or  equipment  in the  ordinary
course of business;

                  (d) sales,  transfers or other  dispositions  pursuant to bona
fide  sale-leaseback  financings  in which the lease  (i) gives  rise  solely to
Capital  Lease  Obligations  and (ii) is a Permitted  Capital  Lease;  provided,
however, that any such sales,  transfers or other dispositions are not permitted
with any assets of the communications network;

                  (e) sales,  transfers,  or other dispositions of assets in the
ordinary  course of business  having a fair market value not exceeding  $500,000
per item or  $1,000,000 in the  aggregate in any fiscal year  (excluding  sales,
transfers and  dispositions  theretofore  approved in accordance  with the terms
hereof in such fiscal year);

                  (f)  sales,  transfers  or other  dispositions  of  assets  to
Skycell to be used in connection with the sales and marketing of services of the
Borrower  and  having  a fair  market  value  not  exceeding  $5,000,000  in the
aggregate during the term of this Agreement;

                  (g) sales,  transfers or other dispositions of contract rights
under  subscriber  equipment  leases pursuant to any bona fide financing of such
leases;

                  (h)  non-exclusive licenses of technology and other
intangible assets;

                  (i)  sales of mobile earth terminals and related equipment,
and other inventory;

                  (j) any  Subsidiary of the Borrower may merge,  consolidate or
combine  with  or  into,  or  transfer  assets  to the  Borrower  or one or more
Subsidiaries of the Borrower; provided that with respect to any such transaction
involving  the  Borrower,  the  Borrower  shall be the  continuing  or surviving
corporation  and if any such  transaction  shall be between a  Subsidiary  and a
wholly-owned Subsidiary,  the wholly-owned Subsidiary shall be the continuing or
surviving corporation;

                  (k) any Subsidiary of the Borrower may sell,  lease,  transfer
or otherwise dispose of any or all of its assets (upon voluntary  liquidation or
otherwise),  to the Borrower or another wholly-owned Subsidiary of the Borrower;
and

                                       54





                  (l) the Borrower or any Subsidiary  may merge,  consolidate or
combine with another entity if the Borrower or the Subsidiary,  respectively, is
the corporation surviving the merger.

                  SECTION  4.19.  Principal  Subsidiary  Guaranties.  The Parent
Guarantor and the Borrower shall cause each Subsidiary which becomes a Principal
Subsidiary after the date hereof to execute and deliver to the Common Collateral
Agent a Principal Subsidiary Guaranty.

                  SECTION 4.20. Employee Contracts and Arrangements. Neither the
Parent  Guarantor  nor the Borrower  shall,  nor shall either  permit any of its
Subsidiaries  to,  enter into any  employment  contracts or  arrangements  whose
terms, including salaries,  benefits and other compensation,  are not normal and
customary  and   commercially   reasonable   for  companies  of  like  size  and
circumstances.

                  SECTION  4.21.  Loans  and  Investments.  Neither  the  Parent
Guarantor nor the Borrower shall,  directly or indirectly,  purchase or acquire,
or permit any member of the Parent  Guarantor  Group to purchase or acquire,  or
make any commitment therefor, any capital stock, equity interest, obligations or
other securities of or any interest in, any Person,  or make any advance,  loan,
extension of credit or capital  contribution to or any other  investment in, any
Person including, without limitation, any Affiliates of the Borrower, except for
("Permitted Investments"):

                  (a)  investments in Cash Equivalents;

                  (b) extensions of credit in the nature of accounts  receivable
or notes  receivable  arising from the sale or lease of goods or services in the
ordinary course of business;

                  (c)  extensions  of  credit  by the  Parent  Guarantor  or the
Borrower  to,  and  investments  in,  any  Principal  Subsidiary  not  exceeding
$5,000,000 in the  aggregate,  provided  that in the case of the Borrower,  such
extensions of credit or investments may only be to or in Principal  Subsidiaries
engaged solely in businesses related to the Project;

                  (d)  extensions  of  credit  by the  Parent  Guarantor  or the
Borrower to, and investments in, Joint Ventures not exceeding  $5,000,000 in the
aggregate at any time, provided that such extensions of credit or investments by
the Borrower may only be to or in Joint  Ventures  engaged  solely in businesses
related to the Project;

                  (e) prudent extensions of credit not exceeding $500,000 in the
aggregate to officers and other key employees of the Borrower to retain them in,
or to induce them to enter into, the employ of the Borrower;

                  (f)  equity investments by the Parent Guarantor in or
capital contributions by the Parent Guarantor to a wholly-owned Subsidiary

                                       55





of  the  Parent  Guarantor  that  is not a  Subsidiary  of  the  Borrower  (such
Subsidiary,   the  "Second  Satellite   Subsidiary")  that  (i)  do  not  exceed
$100,000,000  in the aggregate,  (ii) are used by such Subsidiary to finance the
development and  construction of an additional  satellite used to provide mobile
communications  services  throughout the United States and (iii) are made solely
from the cash  proceeds of the  issuance  and sale of equity  securities  of the
Parent  Guarantor  or any  Excess  Cash  Flow  not  required  to be  applied  to
prepayment of the Loans pursuant to Section 2.4(b)(i); and

                  (g)  investments by the Parent Guarantor in the Borrower.

                  SECTION 4.22.  Limitation on Indebtedness.  Neither the Parent
Guarantor  nor the Borrower  shall,  nor shall  either  permit any member of the
Parent Guarantor Group to, create, incur, assume, guaranty,  suffer to exist, or
otherwise  become or remain  directly or indirectly  liable with respect to, any
Indebtedness, except for:

                  (a) accounts payable to trade creditors for goods and services
and current  operating  liabilities  (not the result of the  borrowing of money)
incurred in the ordinary course of the Parent Guarantor's, the Borrower's or the
Subsidiary's  business,  as the case may be, in accordance  with customary terms
and  paid  within  the  specified  time,  unless  contested  in  good  faith  by
appropriate proceedings and reserved for in accordance with GAAP;

                  (b)  Indebtedness represented by Rate Contracts;

                  (c)  income taxes payable and deferred taxes;

                  (d)  accrued expenses and deferred income;

                  (e)  Vendor Debt;

                  (f)  Indebtedness under Permitted Capital Leases;

                  (g)  Indebtedness under the Revolving Credit Agreement;

                  (h)  Contingent  Obligations  incurred in connection  with any
lease financing of mobile communications  terminals, not exceeding $5,000,000 in
the aggregate in principal amount;

                  (i)  prior to the initial Borrowing, Indebtedness under
Bridge Notes and the Interim Notes; and

                  (j) Indebtedness  under the Financial  Management Account Line
of  Credit  of the  Borrower  payable  to the  order of  Wachovia  Bank of North
Carolina,  N.A.,  in an  aggregate  principal  amount at any time not  exceeding
$2,500,000.

                  SECTION 4.23.  Transactions with Affiliates.  Neither the
Parent Guarantor nor the Borrower shall, nor shall either permit any
member of the Parent Guarantor Group to enter into any transaction with

                                       56





any Affiliate of such Person except as  contemplated by this Agreement or in the
ordinary  course of business and pursuant to the reasonable  requirements of the
business of such Person and upon fair and reasonable  terms no less favorable to
such Person than would obtain in a comparable  arm's-length  transaction  with a
Person not an Affiliate  of such  Person.  Notwithstanding  the  foregoing,  the
Borrower  shall  be  permitted  to  enter  into  and  perform  the  transactions
contemplated  by (a) the Commission  Sales Agency  Agreement dated July 1, 1995,
between  the  Borrower  and  Skycell,  as  amended to the date  hereof,  (b) the
Intercorporate  Services  Agreement dated July 1, 1995, between the Borrower and
Skycell, as amended to the date hereof, (c) the Commission  Agreement dated July
1, 1995,  between the Borrower and Sales Co., as amended to the date hereof, (d)
the Guaranty Issuance  Agreement and the warrants issued pursuant  thereto,  (e)
the Standstill  Agreement among the Parent Guarantor,  the Borrower,  Hughes and
Hughes Communications  Satellite Services,  Inc., dated as of June 28, 1996, (f)
the  Registration  Rights  Agreement dated as of June 28, 1996, among the Parent
Guarantor,  Hughes, ST and Baron Capital,  (g) the Securities Purchase Agreement
dated as of January 19, 1996,  among the  Borrower,  the Parent  Guarantor,  the
Purchasers listed on the signature pages thereof and the Toronto-Dominion  Bank,
as Payment Agent for such  Purchasers,  and the warrants issued pursuant thereto
and (h) the  Registration  Rights  Agreement dated as of January 19, 1996, among
the  Parent  Guarantor  and the  other  persons  listed on the  signature  pages
thereof.

                  SECTION  4.24.  Compliance  with  ERISA.  Neither  the  Parent
Guarantor nor the Borrower shall directly or indirectly,  and neither the Parent
Guarantor  nor the  Borrower  shall  permit any member of the  Controlled  Group
directly or indirectly (i) to terminate,  any Qualified Plan subject to Title IV
of ERISA, so as to result in any material (in the opinion of the Required Banks)
liability to the Borrower or any member of the Controlled  Group, (ii) to permit
to exist any ERISA Event,  which presents the risk of a material (in the opinion
of the Required Banks) liability of any member of the Controlled Group, or (iii)
to make a complete or partial  withdrawal  (within the meaning of ERISA  Section
4201)  from any  Multiemployer  Plan so as to  result  in any  material  (in the
opinion of the Required Banks)  liability to any member of the Controlled  Group
or (iv) permit the present value of all  nonforfeitable  accrued  benefits under
each Qualified Plan (using the actuarial  assumptions  utilized by the PBGC upon
termination  of a Qualified  Plan)  materially  (in the opinion of the  Required
Banks) to exceed the fair market  value of  Qualified  Plan assets  allocable to
such benefits, all determined as of the most recent valuation date for each such
Qualified Plan.

                  SECTION 4.25. Project Documents.  Neither the Parent Guarantor
nor the Borrower shall,  nor shall it permit any of its  Subsidiaries to, modify
or amend any of the Project Documents in any respect,  or waive any provision or
condition  contained  therein,  except with the express  written  consent of the
Required Banks.

                  SECTION 4.26.  Lease Obligations.  Neither the Parent
Guarantor nor the Borrower shall, nor shall it permit any member of the

                                       57





Parent  Guarantor  Group to, create or suffer to exist any  obligations  for the
payment of rent for any property under lease or agreement to lease, except for

                  (a)  leases in existence on the Effective Date and any
renewal, extension or refinancing thereof;

                  (b)  after the Effective Date, any leases (other than
capital leases) entered into in the ordinary course of business; and

                  (c) after the Effective Date,  capital leases other than those
permitted  under clause (a) of this Section 5.26 to finance the  acquisition  of
equipment,  provided  that the  aggregate  annual  rental  payments for all such
capital  leases,  together with the aggregate  principal  amount of Indebtedness
secured by Liens permitted under Section 5.17(g), shall not exceed $15,000,000.

                  SECTION  4.27.   Restricted   Payments.   Neither  the  Parent
Guarantor nor the Borrower  shall declare or make any dividend  payment or other
distribution of assets,  properties,  cash, rights, obligations or securities on
account of any shares of any class of its capital  stock or purchase,  redeem or
otherwise  acquire for value (or permit any member of the Parent Guarantor Group
to do so) any shares of its capital stock or any warrants,  rights or options to
acquire such shares, now or hereafter outstanding, provided that:

                           (x) so long as no  Default  or Event of  Default  has
         occurred and is continuing or would result therefrom,  the Borrower may
         distribute to the Parent  Guarantor Excess Cash Flow not required to be
         applied to prepayment of the Loans pursuant to Section  2.4(b),  solely
         for  the  purpose  of  enabling  the  Parent   Guarantor  to  make  the
         Investments and capital contributions permitted by Section 5.21(f);

                           (y) so long as no  Default  or Event of  Default  has
         occurred and is  continuing  or would result  therefrom,  Sales Co. may
         make  distributions to the Parent  Guarantor,  provided that the Parent
         Guarantor  promptly  contributes  any  assets  so  distributed  to  the
         Borrower; and

                           (z) the Parent  Guarantor  may exchange  Common Stock
         for Bridge Notes in accordance with the terms of the Bridge Agreement.

                  SECTION 4.28.  Leverage  Ratio.  The Leverage  Ratio as of the
last day of any fiscal  quarter  ending during a period set forth below will not
exceed the ratio set forth opposite such period below:

Period                                                                    Ratio

June 30, 1998 through September 29, 1998                               14.5 to 1
September 30, 1998 through December 30, 1998                            7.5 to 1
December 31, 1998 through March 30, 1999                                5.0 to 1
Thereafter                                                              3.0 to 1

                                       58






                  SECTION 4.29.  Balance Sheet Leverage Ratio.  The ratio of (i)
Indebtedness  of the Parent  Guarantor Group to (ii)  Consolidated  Tangible Net
Worth will at no time during any of the periods set forth below exceed the ratio
set forth opposite such period below:

Period                                                                     Ratio

June 30, 1997 through September 29, 1997                               1.50 to 1
September 30, 1997 through December 30, 1997                           1.75 to 1
December 31, 1997 through March 30, 1998                               2.00 to 1
March 31, 1998 through September 29, 1998                              2.40 to 1
September 30, 1998 through December 30, 1998                           2.10 to 1
December 31, 1998 through March 30, 1999                               1.75 to 1
March 31, 1999 through June 29, 1999                                   1.30 to 1
June 30, 1999 through September 29, 1999                               1.00 to 1
Thereafter                                                             0.50 to 1

                  SECTION 4.30. Indebtedness Per Subscriber. Indebtedness of the
Parent  Guarantor  Group  divided by the number of  Subscribers  will at no time
during any of the periods set forth below  exceed the amount set forth  opposite
such period:


Maximum                                          Indebtedness
Period                                          per Subscriber

June 30, 1997 through September 29, 1997           $4,300
September 30, 1997 through December 30, 1997        3,500
December 31, 1997 through March 30, 1998            3,100
March 31, 1998 through June 29, 1998                2,600
June 30, 1998 through September 29, 1998            2,000
September 30, 1998 through December 30, 1998        1,700
December 31, 1998 through March 30, 1999            1,400
Thereafter                                          1,000

                  SECTION 4.31. Minimum  Performance.  The number of Subscribers
as of the last day of any three month period specified below and Net Revenue for
any three  month  period  specified  below  shall not be less than the number or
amount, respectively, set forth opposite such three month period below:

                                       59






         Three Months               Minimum          Minimum Net
         Ending                     Subscribers      Revenue

         June 30, 1997                38,000         $14,000,000
         September 30, 1997           50,000          18,000,000
         December 31, 1997            60,000          22,000,000
         March 31, 1998               80,000          28,000,000
         June 30, 1998                95,000          35,000,000
         September 30, 1998          110,000          42,000,000
         December 31, 1998           130,000          50,000,000

                  SECTION 4.32.  Interest Coverage.  The Interest Coverage Ratio
as of the last day of any fiscal quarter ending during a period  specified below
will not be less than the ratio set forth opposite such period below:

Period                                                             Minimum Ratio
September 30, 1998 through December 30, 1998                           1.75 to 1
December 31, 1998 through March 30, 1999                                3.0 to 1
March 31, 1999 through June 29, 1999                                    4.0 to 1
Thereafter                                                              5.0 to 1



                  SECTION  4.33.  Capital  Expenditures.  The  Borrower  and the
Parent  Guarantor  will  not,  and will not  permit  any  member  of the  Parent
Guarantor Group to, make any Consolidated  Capital  Expenditures  other than for
the purchase of (i) assets in furtherance of its mobile communications and other
related  businesses,  including  the  Project,  (ii) fixed  assets  and  capital
equipment which are expressly contemplated by and budgeted for under the capital
expenditures budget then in effect, (iii) such other assets which would increase
the value, economic or operational efficiency of the Project and which would not
reasonably be expected to have a Material  Adverse Effect and (iv) assets in the
ordinary  course  of  business   reasonably  required  in  connection  with  the
maintenance,  marketing or operation of the Project; provided that the aggregate
of all Capital  Expenditures  by the Parent  Guarantor Group in each of 1997 and
1998 shall in no event exceed $40,000,000.

                  SECTION 4.34.  Change in Structure.  Except as permitted under
Section 5.18,  neither the Parent  Guarantor nor the Borrower will, nor will the
Parent  Guarantor  permit  any  of its  Principal  Subsidiaries  or  the  Second
Satellite  Subsidiary to, nor the Borrower  permit any of its  Subsidiaries  to,
make any changes in its capital structure (including, without limitation, in the
terms of its  outstanding  stock) or amend its certificate of  incorporation  or
by-laws if, as a result,  there would be a reasonable  likelihood  of a Material
Adverse Effect.

                  SECTION 4.35.  Accounting Changes.  Neither the Borrower nor
the Parent Guarantor will, nor will permit any member of the Parent
Guarantor Group to, make any significant change in accounting treatment

                                       60





and reporting  practices,  except as required by GAAP, or change the fiscal year
of the Parent Guarantor or any of its Subsidiaries.

                  SECTION  4.36.  Rate  Contracts.  Within  180 days  after  the
Release Date the Borrower will enter into or obtain, and thereafter  maintain in
full force and effect, Rate Contracts in all respects reasonably satisfactory to
the  Agents  as to the  extent  required  to  effectively  fix for two years the
interest cost on at least 50% of the  aggregate  amount of  Indebtedness  of the
Borrower  at a rate not to  exceed  the sum of 2% plus the  rate in  effect  for
United States Treasury  securities with a maturity of two years on the date such
Rate Contracts are entered into.


                                    ARTICLE 5

                                    DEFAULTS

                  SECTION 5.1.  Events of Default.  If one or more of the
following events ("Events of Default") shall have occurred and be
continuing:

                  (a)  the  Borrower,  the  Parent  Guarantor  or any  Principal
         Subsidiary (other than the Borrower) shall fail to pay any principal of
         any Loan when due or any interest, any fees or any other amount payable
         hereunder within two Business Days of the date when due;

                  (b) the Borrower or the Parent Guarantor shall fail to observe
         or  perform  any  covenant  contained  in  Article  5, other than those
         contained in Sections 5.1 through 5.5, 5.7 through 5.10, 5.14 and 5.15;
         provided that the failure to observe or perform the covenants contained
         in Sections  5.28 through 5.32 and the proviso to Section 5.33 prior to
         the  Release  Date shall not  constitute  an Event of Default  unless a
         Guarantor Event shall have occurred;

                  (c) the Borrower or the Parent Guarantor shall fail to observe
         or perform any covenant or agreement contained in this Agreement (other
         than those covered by clause (a) or (b) above) for 20 days after notice
         thereof has been given to the Borrower by the  Administrative  Agent at
         the request of any Bank;

                  (d) any representation,  warranty,  certification or statement
         made by the Borrower or the Parent  Guarantor  in this  Agreement or in
         any  certificate,  financial  statement  or  other  document  delivered
         pursuant to this  Agreement  shall prove to have been  incorrect in any
         material respect when made (or deemed made);

                  (e) the Parent  Guarantor or any Subsidiary shall fail to make
         any payment in respect of any  Indebtedness  or  Contingent  Obligation
         having an aggregate  principal and face amount of more than  $5,000,000
         when  due  (whether  by  scheduled   maturity,   required   prepayment,
         acceleration, demand or otherwise) and such failure

                                       61





         continues after the applicable grace period or notice period, if
         any, specified in the document relating thereto;

                  (f) any event or  condition  shall occur which  results in the
         acceleration  of  the  maturity  of  any   Indebtedness  or  Contingent
         Obligation  of the Parent  Guarantor  or any  Subsidiary  of the Parent
         Guarantor  having an  aggregate  principal  or face amount of more than
         $5,000,000  or enables (or,  with the giving of notice or lapse of time
         or both,  would enable) the holder of such  Indebtedness  or Contingent
         Obligation or any Person  acting on such holder's  behalf to accelerate
         the maturity thereof;

                  (g) the Parent  Guarantor or any  Principal  Subsidiary  shall
         commence a  voluntary  case or other  proceeding  seeking  liquidation,
         reorganization  or other  relief  with  respect  to itself or its debts
         under any bankruptcy,  insolvency or other similar law now or hereafter
         in  effect  or  seeking  the   appointment  of  a  trustee,   receiver,
         liquidator,   custodian  or  other  similar   official  of  it  or  any
         substantial  part of its property,  or shall consent to any such relief
         or to the  appointment of or taking  possession by any such official in
         an involuntary case or other proceeding  commenced against it, or shall
         make a general  assignment for the benefit of creditors,  or shall fail
         generally  to pay its  debts as they  become  due,  or  shall  take any
         corporate action to authorize any of the foregoing;

                  (h) an involuntary case or other proceeding shall be commenced
         against  the  Parent  Guarantor  or any  Principal  Subsidiary  seeking
         liquidation,  reorganization  or other relief with respect to it or its
         debts  under any  bankruptcy,  insolvency  or other  similar law now or
         hereafter in effect or seeking the appointment of a trustee,  receiver,
         liquidator,   custodian  or  other  similar   official  of  it  or  any
         substantial  part of its property,  and such  involuntary case or other
         proceeding  shall  remain  undismissed  and unstayed for a period of 60
         days;  or an order for  relief  shall be  entered  against  the  Parent
         Guarantor or any Principal Subsidiary under the federal bankruptcy laws
         as now or hereafter in effect;

                  (i) (1) any member of the  Controlled  Group shall fail to pay
         when due,  after the  expiration of any  applicable  grace period,  any
         installment  payment with respect to its withdrawal  liability  under a
         Multiemployer  Plan; (2) any member of the Controlled  Group shall fail
         to satisfy its contribution  requirements  under Section  412(c)(11) of
         the Code, whether or not it has sought a waiver under Section 412(d) of
         the Code;  (3) in the case of an ERISA Event  involving the  withdrawal
         from  a  Plan  of a  "substantial  employer"  (as  defined  in  Section
         4001(a)(2) or Section  4062(e) of ERISA),  the  withdrawing  employer's
         proportionate share of that Plan's Unfunded Pension Liabilities is more
         than $5,000,000 or 10% of its net worth, if greater; (4) in the case of
         an ERISA Event  involving  the  complete or partial  withdrawal  from a
         Multiemployer Plan, the withdrawing  employer has incurred a withdrawal
         liability in an aggregate amount exceeding $5,000,000 or 10% of its net

                                       62





         worth,  if greater;  (5) in the case of an ERISA Event not described in
         clause (3) or (4), the  Unfunded  Pension  Liabilities  of the relevant
         Plan or Plans exceed  $5,000,000  or 10% of its net worth,  if greater;
         (6) a Plan that is intended to be qualified under Section 401(a) of the
         Code  shall  lose its  qualification,  and the loss can  reasonably  be
         expected to impose on any member of the Controlled Group liability (for
         additional taxes, to Plan participants,  or otherwise) in the aggregate
         amount of $5,000,000 or 10% of its net worth,  if greater or more;  (7)
         the commencement or increase of  contributions  to, the adoption of, or
         the  amendment of a Plan by, any member of the  Controlled  Group shall
         result in a net increase in unfunded  liabilities to the Borrower or an
         ERISA  Affiliate  in  excess  of  $5,000,000  or 10% of net  worth,  if
         greater;  or (8) the occurrence of any  combination of events listed in
         clauses  (3)  through (7) that  involves a net  increase  in  aggregate
         Unfunded  Pension  Liabilities  and unfunded  liabilities  in excess of
         $5,000,000 or 10% of its net worth, if greater;

                  (j) one or more final  judgments,  orders or decrees  shall be
         entered  against  the  Parent  Guarantor  or any  member of the  Parent
         Guarantor  Group  involving  in the  aggregate a  liability  (not fully
         covered by insurance  and as to which the insurer has not  acknowledged
         liability)  more than an amount equal to the greater of (i)  $5,000,000
         and (ii) 10% of the Parent  Guarantor's  net worth,  and the same shall
         remain unvacated, undischarged, unstayed or unbonded pending appeal for
         a period of 60 days after the entry thereof; or

                  (k) any  non-monetary  judgment,  order  or  decree  shall  be
         rendered against the Parent Guarantor or any of its Subsidiaries  which
         could  reasonably be expected to have a Material  Adverse  Effect,  and
         enforcement  proceedings  shall have been  commenced by any Person upon
         such judgment or order which shall remain unstayed for any period of 10
         consecutive days or more; or

                  (l) (i) any provision of any Common Collateral  Document shall
         for any reason cease to be valid and binding on or enforceable  against
         the Parent Guarantor,  the Borrower or any of its Subsidiaries,  if the
         effect thereof may  materially  deprive the Banks and the Agents of the
         benefits  of the  Common  Collateral  covered  thereby,  or the  Parent
         Guarantor or any of its Subsidiaries shall so state in writing or bring
         an action to limit its obligations or liabilities thereunder;  (ii) the
         Common  Collateral  Documents shall for any reason (other than pursuant
         to, or  contemplated  by,  the terms  thereof)  cease to create a valid
         security  interest  in the Common  Collateral  purported  to be covered
         thereby or such  security  interest  shall for any reason cease to be a
         perfected and (except for Permitted  Liens arising by operation of law)
         first  priority  security  interest;   (iii)  any  of  the  outstanding
         Obligations of the Borrower hereunder shall not be Secured  Obligations
         (as defined in the Intercreditor  Agreement); or (iv) there shall occur
         an Event of Loss which,  together  with all other  Events of Loss since
         the Effective Date, results in a reduction in the value (as

                                       63





         determined  in the  reasonable  opinion of the  Required  Banks) of the
         Common  Collateral of $2,500,000  net of any cash proceeds  received by
         the Borrower in respect of such Event or Events of Loss;

                  (m) the FCC or any other  Governmental  Authority shall revoke
         or fail to renew the FCC License or any other material license,  permit
         or  franchise  of the  Parent  Guarantor  or  any  of its  Subsidiaries
         relating to the Project; the Borrower shall for any reason lose the FCC
         License or any other material license,  permit or franchise relating to
         the  Project;  or the  Borrower  shall  suffer  the  imposition  of any
         restraining order, escrow, suspension or impound of funds in connection
         with any proceeding  (judicial or  administrative)  with respect to the
         FCC License or any other material license, permit or franchise relating
         to the Project;

                  (n)   there shall occur and be continuing a Material Adverse
         Effect;

                  (o) The  Borrower  shall  breach  or  default  under  any Rate
         Contract to which any Bank is a party,  if the effect of such breach or
         default is to allow the Bank to proceed against,  or otherwise  realize
         from, the Borrower or any Common Collateral to satisfy any claim of the
         Bank against the Borrower in respect of such Rate Contract;

                  (p) any provision of Article 9 of this Agreement shall for any
         reason be  revoked or  invalidated,  or  otherwise  cease to be in full
         force and effect;

                  (q)  there shall occur a Change in Control;

                  (r)  prior to the  Release  Date,  any  Shareholder  Guarantor
         (other  than  Baron  Capital)  shall  fail to make any  payment  (i) in
         respect  of  any  Indebtedness  or  Contingent   Obligation  having  an
         aggregate  principal  or face amount of more than  $50,000,000  or (ii)
         under its Shareholder Guaranty when due (whether by scheduled maturity,
         required  prepayment,  acceleration,  demand  or  otherwise)  and  such
         failure  continues after the applicable  grace period or notice period,
         if any, specified in the document relating thereto;

                  (s) prior to the Release  Date,  any event or condition  shall
         occur  which  results  in  the  acceleration  of  the  maturity  of any
         Indebtedness  of  Contingent  Obligation of any  Shareholder  Guarantor
         (other than Baron Capital) having an aggregate principal or face amount
         of more than $50,000,000 or enables the holder of such  Indebtedness or
         Contingent  Obligation or any Person acting on such holder's  behalf to
         accelerate the maturity thereof;

                  (t) prior to the Release Date, any Shareholder Guaranty or the
         Baron  Capital  Letter of Credit  shall for any  reason be  revoked  or
         invalidated or otherwise  cease to be in full force and effect prior to
         the Release Date; or

                                       64





                  (u) prior to the  Release  Date,  the  Shareholder  Guarantors
         shall have failed to purchase all of the rights and obligations of each
         Bank under this Agreement and the Notes pursuant to Section 1(e) of the
         Shareholder  Guaranties and Section  10.6(e) of this  Agreement  within
         five Business Days of the occurrence of a Guarantor Event;

then, and in every such event, the  Administrative  Agent shall (i) if requested
by Banks having more than 50% in aggregate amount of the Commitments,  by notice
to the Borrower  terminate the Commitments  and they shall thereupon  terminate,
and (ii) if requested by Banks holding more than 50% of the aggregate  principal
amount of the Loans, by notice to the Borrower  declare the Loans (together with
accrued  interest  thereon)  to  be,  and  the  Loans  shall  thereupon  become,
immediately due and payable without presentment, demand, protest or other notice
of any kind,  all of which are hereby waived by the  Borrower;  provided that in
the case of any of the Events of Default  specified  in clause  6.1(g) or 6.1(h)
above with  respect to the  Borrower,  without any notice to the Borrower or any
other  act by the  Administrative  Agent or the  Banks,  the  Commitments  shall
thereupon terminate and the Loans (together with accrued interest thereon) shall
become immediately due and payable without presentment, demand, protest or other
notice of any kind, all of which are hereby waived by the Borrower.

                  SECTION 5.2. Notice of Default. The Administrative Agent shall
give notice to the Borrower under Section 6.1(c)  promptly upon being  requested
to do so by any Bank and shall thereupon notify all the Banks thereof.


                                    ARTICLE 6

                                   THE AGENTS

                  SECTION  6.1.   Appointment  and   Authorization.   Each  Bank
irrevocably  appoints and authorizes  each Agent to take such action as agent on
its behalf and to exercise such powers under this Agreement and the Notes as are
delegated to such Agent by the terms hereof or thereof,  together  with all such
powers as are reasonably incidental thereto.

                  SECTION 6.2.  Agents and  Affiliates.  Morgan  Guaranty  Trust
Company of New York shall have the same rights and powers  under this  Agreement
as any other Bank and may exercise or refrain from exercising the same as though
it were not an Agent,  and each of Toronto  Dominion  (Texas),  Inc.  and Morgan
Guaranty Trust Company of New York and its affiliates may accept  deposits from,
lend  money to, and  generally  engage in any kind of  business  with the Parent
Guarantor or any  Subsidiary or affiliate of the Parent  Guarantor as if it were
not an Agent.

                  SECTION 6.3.  Action by Agents.  The obligations of the
Agents hereunder are only those expressly set forth herein.  Without
limiting the generality of the foregoing, the Agents shall not be

                                       65





required to take any action with  respect to any  Default,  except as  expressly
provided in Article 6.

                  SECTION  6.4.  Consultation  with  Experts.  Either  Agent may
consult  with legal  counsel  (who may be counsel for the Borrower or the Parent
Guarantor),  independent public accountants and other experts selected by it and
shall not be liable  for any  action  taken or omitted to be taken by it in good
faith in accordance with the advice of such counsel, accountants or experts.

                  SECTION  6.5.  Liability  of  Agents.  No  Agent or any of its
affiliates or any of their respective directors,  officers,  agents or employees
shall be liable for any action taken or not taken by it in  connection  herewith
(i) with the  consent  or at the  request of the  Required  Banks or (ii) in the
absence of its own gross  negligence or willful  misconduct.  No Agent or any of
its  affiliates  or any of  their  respective  directors,  officers,  agents  or
employees shall be responsible  for or have any duty to ascertain,  inquire into
or verify (i) any statement,  warranty or representation made in connection with
this Agreement or any borrowing hereunder; (ii) the performance or observance of
any of the  covenants or  agreements  of the  Borrower or the Parent  Guarantor;
(iii) the  satisfaction of any condition  specified in Article 3, except receipt
of items  required  to be  delivered  to the  Documentation  Agent;  or (iv) the
validity, effectiveness or genuineness of this Agreement, the Notes or any other
instrument or writing furnished in connection herewith. No Agent shall incur any
liability  by  acting  in  reliance  upon  any  notice,  consent,   certificate,
statement,  or  other  writing  (which  may be a  bank  wire,  telex,  facsimile
transmission or similar writing) believed by it to be genuine or to be signed by
the proper party or parties.

                  SECTION  6.6.  Indemnification.  Each Bank  shall,  ratably in
accordance with its Commitment,  indemnify each Agent,  its affiliates and their
respective  directors,  officers,  agents  and  employees  (to  the  extent  not
reimbursed by the Borrower or the Parent  Guarantor)  against any cost,  expense
(including  counsel fees and  disbursements),  claim,  demand,  action,  loss or
liability  (except  such as result from such  indemnitee'  gross  negligence  or
willful  misconduct) that such indemnitee may suffer or incur in connection with
this Agreement or any action taken or omitted by such indemnitee hereunder.

                  SECTION 6.7. Credit Decision.  Each Bank  acknowledges that it
has, independently and without reliance upon either Agent or any other Bank, and
based on such documents and information as it has deemed  appropriate,  made its
own credit  analysis and decision to enter into this  Agreement.  Each Bank also
acknowledges that it will,  independently and without reliance upon either Agent
or any other Bank, and based on such documents and  information as it shall deem
appropriate at the time,  continue to make its own credit decisions in taking or
not taking any action under this Agreement.

                  SECTION 6.8.  Successor Agent.  Either Agent may resign at
any time by giving notice thereof to the Banks and the Borrower.  Upon

                                       66





any such  resignation,  the  Required  Banks  shall  have the right to appoint a
successor  Agent.  If no  successor  Agent shall have been so  appointed  by the
Required Banks, and shall have accepted such  appointment,  within 30 days after
the retiring Agent gives notice of resignation,  then the retiring Agent may, on
behalf of the Banks, appoint a successor Agent, which shall be a commercial bank
organized or licensed  under the laws of the United  States of America or of any
State thereof and having a combined capital and surplus of at least $50,000,000.
Upon the acceptance of its appointment as Agent hereunder by a successor  Agent,
such successor Agent shall  thereupon  succeed to and become vested with all the
rights  and  duties of the  retiring  Agent,  and the  retiring  Agent  shall be
discharged from its duties and obligations hereunder. After any retiring Agent's
resignation  hereunder as Agent,  the  provisions of this Article shall inure to
its  benefit as to any  actions  taken or omitted to be taken by it while it was
Agent.

                  SECTION 6.9.  Agents' Fees.  The Borrower shall pay to each
Agent for its own account fees in the amounts and at the times previously
agreed upon between the Borrower and such Agent.


                                    ARTICLE 7

                             CHANGE IN CIRCUMSTANCES

                  SECTION 7.1.  Basis for Determining Interest Rate Inadequate
or Unfair.  If on or prior to the first day of any Interest Period for
any Euro-Dollar Loan:

                  (a) the Administrative Agent is advised by the Reference Banks
         that  deposits in dollars  (in the  applicable  amounts)  are not being
         offered to the Reference Banks in the London  interbank market for such
         Interest Period, or

                  (b) Banks having 50% or more of the aggregate principal amount
         of the affected Loans advise the Administrative Agent that the Adjusted
         London Interbank Offered Rate as determined by the Administrative Agent
         will not  adequately  and  fairly  reflect  the  cost to such  Banks of
         funding their Euro-Dollar Loans for such Interest Period,

the Administrative Agent shall forthwith give notice thereof to the Borrower and
the Banks,  whereupon until the Administrative  Agent notifies the Borrower that
the  circumstances  giving  rise to such  suspension  no longer  exist,  (i) the
obligations  of the Banks to make  Euro-Dollar  Loans or to  continue or convert
outstanding  Loans as or into Euro-Dollar Loans shall be suspended and (ii) each
outstanding  Euro- Dollar Loan shall be  converted  into a Base Rate Loan on the
last day of the then current  Interest  Period  applicable  thereto.  Unless the
Borrower notifies the  Administrative  Agent at least two Domestic Business Days
before the date of any Euro-Dollar Borrowing for which a Notice of Borrowing has
previously  been given that it elects not to borrow on such date, such Borrowing
shall instead be made as a Base Rate Borrowing. The Administrative Agent

                                       67





shall notify the Borrower as soon as reasonably  possible upon learning that the
circumstances giving rise to such suspension no longer exist.

                  SECTION  7.2.  Illegality.  If,  on or after  the date of this
Agreement, the adoption of any applicable law, rule or regulation, or any change
in any applicable law, rule or regulation,  or any change in the  interpretation
or  administration  thereof  by any  governmental  authority,  central  bank  or
comparable agency charged with the interpretation or administration  thereof, or
compliance by any Bank (or its  Euro-Dollar  Lending Office) with any request or
directive  (whether  or not  having  the  force of law) of any  such  authority,
central bank or comparable  agency shall make it unlawful or impossible  for any
Bank  (or its  Euro-Dollar  Lending  Office)  to  make,  maintain  or  fund  its
Euro-Dollar  Loans and such Bank shall so notify the  Administrative  Agent, the
Administrative  Agent shall forthwith give notice thereof to the other Banks and
the  Borrower,   whereupon  until  such  Bank  notifies  the  Borrower  and  the
Administrative  Agent that the  circumstances  giving rise to such suspension no
longer exist,  the  obligation  of such Bank to make  Euro-Dollar  Loans,  or to
convert  outstanding Loans into Euro-Dollar  Loans,  shall be suspended.  Before
giving any notice to the  Administrative  Agent  pursuant to this Section,  such
Bank shall designate a different  Euro-Dollar Lending Office if such designation
will avoid the need for giving such notice and will not, in the judgment of such
Bank, be otherwise  disadvantageous  to such Bank. If such notice is given, each
Euro-Dollar Loan of such Bank then outstanding shall be converted to a Base Rate
Loan either (a) on the last day of the then current  Interest Period  applicable
to such Euro-Dollar Loan if such Bank may lawfully continue to maintain and fund
such Loan to such day or (b)  immediately  if such Bank shall  determine that it
may not lawfully  continue to maintain and fund such Loan to such day. Each Bank
shall notify the  Administrative  Agent and the  Borrower as soon as  reasonably
possible  after the  circumstances  giving rise to any  suspension  by such Bank
described in this Section 8.2 no longer exist.

                  SECTION 7.3.  Increased Cost and Reduced Return.  (a) If on or
after the date hereof,  the adoption of any applicable  law, rule or regulation,
or any change in any applicable  law, rule or  regulation,  or any change in the
interpretation or administration thereof by any governmental authority,  central
bank or comparable  agency  charged with the  interpretation  or  administration
thereof,  or compliance by any Bank (or its Applicable  Lending Office) with any
request  or  directive  (whether  or not  having  the  force of law) of any such
authority,  central  bank or  comparable  agency  shall  impose,  modify or deem
applicable any reserve  (including,  without  limitation,  any such  requirement
imposed by the Board of Governors of the Federal Reserve  System,  but excluding
any such requirement included in an applicable  Euro-Dollar Reserve Percentage),
special deposit,  insurance assessment or similar requirement against assets of,
deposits  with or for the  account of, or credit  extended  by, any Bank (or its
Applicable  Lending  Office)  or shall  impose  on any  Bank (or its  Applicable
Lending Office) or the London interbank market any other condition affecting its
Euro-Dollar  Loans, its Note or its obligation to make Euro-Dollar Loans and the
result of any of the foregoing is to increase the cost to such Bank

                                       68





(or its  Applicable  Lending  Office) of making or maintaining  any  Euro-Dollar
Loan, or to reduce the amount of any sum received or receivable by such Bank (or
its  Applicable  Lending  Office)  under this  Agreement  or under its Note with
respect thereto,  by an amount deemed by such Bank to be material,  then, within
15 days after demand by such Bank (with a copy to the Administrative Agent), the
Borrower  shall pay to such  Bank such  additional  amount  or  amounts  as will
compensate  such Bank for such increased cost or reduction;  provided,  however,
that in the case of an increase  referred to above  resulting from the published
interpretation by a governmental authority,  such Bank shall be entitled to make
demand  on  the  Borrower  in  respect  thereof  only  within  180  days  of the
publication of such interpretation.

                  (b) If any Bank shall  have  determined  that,  after the date
hereof, the adoption of any applicable law, rule or regulation regarding capital
adequacy,  or any change in any such law, rule or  regulation,  or any change in
the  interpretation  or  administration  thereof by any governmental  authority,
central  bank  or  comparable   agency  charged  with  the   interpretation   or
administration  thereof,  or any request or directive regarding capital adequacy
(whether or not having the force of law) of any such authority,  central bank or
comparable agency  (including any  determination by any such authority,  central
bank or comparable  agency that, for purposes of capital adequacy  requirements,
the  Commitments  hereunder  do not  constitute  commitments  with  an  original
maturity of one year or less), has or would have the effect of reducing the rate
of return on  capital  of such Bank (or its  Parent)  as a  consequence  of such
Bank's  obligations  hereunder  to a level  below  that  which such Bank (or its
Parent) could have achieved but for such adoption,  change, request or directive
(taking into  consideration its policies with respect to capital adequacy) by an
amount  deemed by such Bank to be  material,  then from time to time,  within 15
days after demand by such Bank (with a copy to the  Administrative  Agent),  the
Borrower  shall pay to such  Bank such  additional  amount  or  amounts  as will
compensate such Bank (or its Parent) for such reduction; provided, however, that
in the case of an  increase  referred  to  above  resulting  from the  published
interpretation by a governmental authority,  such Bank shall be entitled to make
demand  on  the  Borrower  in  respect  thereof  only  within  180  days  of the
publication of such interpretation.

                  (c) Each  Bank  will  promptly  notify  the  Borrower  and the
Administrative Agent of any event of which it has knowledge, occurring after the
date  hereof,  which will  entitle  such Bank to  compensation  pursuant to this
Section and will designate a different  Lending Office if such  designation will
avoid the need for, or reduce the amount of, such  compensation and will not, in
the  judgment  of such  Bank,  be  otherwise  disadvantageous  to such  Bank.  A
certificate  of any Bank  claiming  compensation  under this Section and setting
forth the  additional  amount or  amounts  to be paid to it  hereunder  shall be
conclusive in the absence of manifest  error. In determining  such amount,  such
Bank may use any reasonable  averaging and attribution  methods.  Each Bank will
notify the Administrative  Agent and the Borrower as soon as reasonably possible
after any  circumstance  entitling  such Bank to  compensation  pursuant to this
Section 8.3(c) no longer exists.


                                       69





                  SECTION 7.4.  Taxes.  (a)  For the purposes of this Section
8.4(a), the following terms have the following meanings:

                  "Taxes"  means any and all  present or future  taxes,  duties,
levies, imposts, deductions, charges or withholdings with respect to any payment
by the Borrower or the Parent  Guarantor,  as the case may be,  pursuant to this
Agreement or under any Note, and all liabilities with respect thereto, excluding
(i) in the  case of each  Bank and  Agent,  taxes  imposed  on its  income,  and
franchise or similar  taxes imposed on it, by a  jurisdiction  under the laws of
which  such  Bank or Agent  (as the case may be) is  organized  or in which  its
principal executive office is located or, in the case of each Bank, in which its
Applicable  Lending  Office is located  and (ii) in the case of each  Bank,  any
United  States  withholding  tax imposed on such payments but only to the extent
that such Bank is subject to United States withholding tax at the time such Bank
first becomes a party to this Agreement.

                  "Other Taxes" means any present or future stamp or documentary
taxes and any other  excise or  property  taxes,  or similar  charges or levies,
which arise from any payment made  pursuant to this  Agreement or under any Note
or from the  execution  or  delivery  of, or  otherwise  with  respect  to, this
Agreement or any Note.

                  (b)  Any  and  all  payments  by the  Borrower  or the  Parent
Guarantor to or for the account of any Bank or Agent hereunder or under any Note
shall be made without deduction for any Taxes or Other Taxes;  provided that, if
the  Borrower  or the Parent  Guarantor  shall be  required by law to deduct any
Taxes  or Other  Taxes  from any such  payments,  (i) the sum  payable  shall be
increased as necessary so that after making all required  deductions  (including
deductions  applicable to additional  sums payable under this Section) such Bank
or Agent (as the case may be)  receives an amount equal to the sum it would have
received  had no such  deductions  been made,  (ii) the  Borrower  or the Parent
Guarantor,  as the case may be, shall make such  deductions,  (iii) the Borrower
shall pay the full amount deducted to the relevant  taxation  authority or other
authority in accordance  with applicable law and (iv) the Borrower or the Parent
Guarantor, as the case may be, shall furnish to the Administrative Agent, at its
address  referred to in Section  10.1,  the  original  or a certified  copy of a
receipt evidencing payment thereof.

                  (c) The Borrower  agrees to indemnify  each Bank and Agent for
the full  amount of Taxes or Other Taxes  (including,  without  limitation,  any
Taxes or Other Taxes imposed or asserted by any  jurisdiction on amounts payable
under  this  Section)  paid by such  Bank or Agent  (as the case may be) and any
liability  (including  penalties,   interest  and  expenses,  other  than  those
resulting from any act or failure to act by such Bank) arising therefrom or with
respect thereto.  This  indemnification  shall be paid within 15 days after such
Bank or Agent (as the case may be) makes demand therefor.


                                       70





                  (d) Each  Bank  organized  under  the  laws of a  jurisdiction
outside the United States, on or prior to the date of its execution and delivery
of this Agreement in the case of each Bank listed on the signature  pages hereof
and on or prior to the date on which it becomes a Bank in the case of each other
Bank,  and from time to time  thereafter if requested in writing by the Borrower
(but only so long as such Bank remains  lawfully  able to do so),  shall provide
the Borrower and the  Administrative  Agent with Internal  Revenue  Service form
1001 or 4224, as  appropriate,  or any successor form prescribed by the Internal
Revenue  Service,  certifying  that such Bank is entitled  to benefits  under an
income tax treaty to which the United  States is a party which  exempts the Bank
from United States  withholding  tax or reduces the rate of  withholding  tax on
payments of interest for the account of such Bank or certifying  that the income
receivable pursuant to this Agreement is effectively  connected with the conduct
of a trade or business in the United States.

                  (e) For any period with  respect to which a Bank has failed to
provide  the  Borrower or the  Administrative  Agent with the  appropriate  form
pursuant to Section  8.4(d)  (unless  such failure is due to a change in treaty,
law or regulation occurring subsequent to the date on which such form originally
was required to be provided), such Bank shall not be entitled to indemnification
under Section  8.4(b) or (c) with respect to Taxes imposed by the United States;
provided that if a Bank,  which is otherwise exempt from or subject to a reduced
rate of  withholding  tax,  becomes  subject to Taxes  because of its failure to
deliver a form required  hereunder,  the Borrower  shall take such steps as such
Bank shall reasonably request to assist such Bank to recover such Taxes.

                  (f) If the Borrower or the Parent Guarantor is required to pay
additional  amounts to or for the account of any Bank  pursuant to this Section,
then such Bank will change the jurisdiction of its Applicable Lending Office if,
in the judgment of such Bank,  such change (i) will eliminate or reduce any such
additional  payment  which  may  thereafter  accrue  and  (ii) is not  otherwise
disadvantageous to such Bank.

                  SECTION  7.5.  Base  Rate  Loans   Substituted   for  Affected
Euro-Dollar  Loans.  If (i) the  obligation  of any  Bank to  make,  or  convert
outstanding Loans to,  Euro-Dollar Loans has been suspended  pursuant to Section
8.2 or (ii) any Bank has  demanded  compensation  under  Section 8.3 or 8.4 with
respect  to its  Euro-Dollar  Loans and the  Borrower  shall,  by at least  five
Euro-Dollar  Business Days' prior notice to such Bank through the Administrative
Agent,  have elected  that the  provisions  of this Section  shall apply to such
Bank,  then,  unless  and  until  such  Bank  notifies  the  Borrower  that  the
circumstances  giving  rise to such  suspension  or demand for  compensation  no
longer exist:

                  (a) all Loans  which would  otherwise  be made by such Bank as
         (or continued as or converted into)  Euro-Dollar Loans shall instead be
         Base Rate  Loans (on which  interest  and  principal  shall be  payable
         contemporaneously  with the  related  Euro-Dollar  Loans  of the  other
         Banks); and

                                       71





                  (b) after each of its  Euro-Dollar  Loans has been  repaid (or
         converted to a Base Rate Loan),  all payments of principal  which would
         otherwise be applied to repay such  Euro-Dollar  Loans shall be applied
         to repay its Base Rate Loans instead.

If such Bank  notifies the Borrower that the  circumstances  giving rise to such
notice no longer apply,  the principal  amount of each such Base Rate Loan shall
be converted  into a  Euro-Dollar  Loan on the first day of the next  succeeding
Interest Period applicable to the related Euro-Dollar Loans of the other Banks.


                                    ARTICLE 8

                                 PARENT GUARANTY

                  SECTION 8.1. The Parent Guaranty.  The Parent Guarantor hereby
unconditionally  guarantees  the full and  punctual  payment  (whether at stated
maturity,  upon  acceleration  or otherwise) of the principal of and interest on
each Note issued by the Borrower  pursuant to this  Agreement,  and the full and
punctual  payment  of all other  amounts  payable  by the  Borrower  under  this
Agreement.  Upon failure by the Borrower to pay punctually any such amount,  the
Parent  Guarantor  shall  forthwith  on demand pay the amount not so paid at the
place and in the manner specified in this Agreement.

                  SECTION 8.2.  Guaranty  Unconditional.  The obligations of the
Parent  Guarantor  hereunder shall be  unconditional  and absolute and,  without
limiting the generality of the foregoing,  shall not be released,  discharged or
otherwise affected by:

                  (i) any extension, renewal, settlement,  compromise, waiver or
         release  in  respect  of any  obligation  of the  Borrower  under  this
         Agreement or any Note, by operation of law or otherwise;

             (ii)  any modification or amendment of or supplement to this
         Agreement or any Note;

            (iii) any release,  impairment,  non-perfection or invalidity of any
         direct or indirect  security for any  obligation of the Borrower  under
         this Agreement or any Note;

             (iv) any change in the corporate existence,  structure or ownership
         of the Borrower, or any insolvency, bankruptcy, reorganization or other
         similar  proceeding  affecting  the  Borrower  or  its  assets  or  any
         resulting  release  or  discharge  of any  obligation  of the  Borrower
         contained in this Agreement or any Note;

                  (v) the existence of any claim,  set-off or other rights which
         the Parent Guarantor may have at any time against the Borrower,  either
         Agent, any Bank or any other Person,  whether in connection herewith or
         any unrelated transactions, provided that nothing herein shall

                                       72





         prevent the assertion of any such claim by separate suit or
         compulsory counterclaim;

             (vi) any invalidity or unenforceability  relating to or against the
         Borrower for any reason of this Agreement or any Note, or any provision
         of applicable  law or regulation  purporting to prohibit the payment by
         the  Borrower of the  principal of or interest on any Note or any other
         amount payable by the Borrower under this Agreement; or

             (vii) any other act or  omission to act or delay of any kind by the
         Borrower,  either  Agent,  any Bank or any  other  Person  or any other
         circumstance  whatsoever  which might,  but for the  provisions of this
         paragraph,  constitute  a legal or  equitable  discharge  of the Parent
         Guarantor's obligations hereunder.

                  SECTION   8.3.   Discharge   Only   Upon   Payment   In  Full;
Reinstatement  In  Certain  Circumstances.  The Parent  Guarantor's  obligations
hereunder shall remain in full force and effect until the Commitments shall have
terminated  and the principal of and interest on the Notes and all other amounts
payable by the Borrower under this Agreement shall have been paid in full. If at
any time any  payment of the  principal  of or interest on any Note or any other
amount  payable by the  Borrower  under this  Agreement  is rescinded or must be
otherwise restored or returned upon the insolvency, bankruptcy or reorganization
of the Borrower or otherwise,  the Parent Guarantor's obligations hereunder with
respect to such payment  shall be reinstated at such time as though such payment
had been due but not made at such time.

                  SECTION  8.4.  Waiver  by the  Parent  Guarantor.  The  Parent
Guarantor irrevocably waives acceptance hereof, presentment, demand, protest and
any notice not provided for herein,  as well as any requirement that at any time
any action be taken by any Person against the Borrower or any other Person.

                  SECTION 8.5. Subrogation.  Until such time as all principal of
and interest on each Note issued by the Borrower  pursuant to this Agreement and
all other amounts payable by the Borrower under this Agreement have indefeasibly
been paid in full, the Parent  Guarantor  shall not asset any rights to which it
may be  entitled,  by  operation  of law or  otherwise,  upon making any payment
hereunder to be  subrogated to the rights of the payee against the Borrower with
respect to such payment or against any direct or indirect security therefor,  or
otherwise to be  reimbursed,  indemnified or exonerated by or for the account of
the Borrower in respect thereof.

                  SECTION 8.6. Stay of Acceleration. If acceleration of the time
for payment of any amount  payable by the Borrower  under this  Agreement or any
Note is stayed upon insolvency,  bankruptcy or  reorganization  of the Borrower,
all such  amounts  otherwise  subject  to  acceleration  under the terms of this
Agreement  shall  nonetheless  be  payable  by the  Parent  Guarantor  hereunder
forthwith  on demand by the  Administrative  Agent  made at the  request  of the
requisite proportion of the Banks specified in Article 6 of the Agreement.

                                       73




                                    ARTICLE 9

                                  MISCELLANEOUS

                  SECTION  9.1.  Notices.   All  notices,   requests  and  other
communications to any party hereunder shall be in writing  (including bank wire,
facsimile transmission or similar writing) and shall be given to such party: (a)
in the case of the  Borrower,  the  Parent  Guarantor  or either  Agent,  at its
address or facsimile number set forth on the signature pages hereof,  (b) in the
case  of any  Bank,  at  its  address  or  facsimile  number  set  forth  in its
Administrative Questionnaire or (c) in the case of any party, such other address
or  facsimile  number as such party may  hereafter  specify  for the  purpose by
notice to the  Agents  and the  Borrower.  Each such  notice,  request  or other
communication  shall be effective (i) if given by facsimile  transmission,  when
transmitted to the facsimile  number  specified in this Section and confirmation
of receipt is received, (ii) if given by mail, 72 hours after such communication
is  deposited  in the mails with  first  class  postage  prepaid,  addressed  as
aforesaid  or (iii) if given by any other means,  when  delivered at the address
specified in this  Section;  provided that notices to the  Administrative  Agent
under Article 2 or Article 8 shall not be effective until received.

                  SECTION  9.2. No Waivers.  No failure or delay by either Agent
or any Bank in exercising any right,  power or privilege  hereunder or under any
Note shall operate as a waiver thereof nor shall any single or partial  exercise
thereof  preclude any other or further  exercise  thereof or the exercise of any
other right,  power or privilege.  The rights and remedies herein provided shall
be cumulative and not exclusive of any rights or remedies provided by law.

                  SECTION 9.3. Expenses; Indemnification. (a) The Borrower shall
pay (i) all out-of-pocket expenses of the Agents,  including reasonable fees and
disbursements  of  special  counsel  for the  Agents,  in  connection  with  the
preparation  and  administration  of  this  Agreement,  any  waiver  or  consent
hereunder or any amendment  hereof or any Default or alleged  Default  hereunder
and (ii) if an Event of Default occurs,  all out-of-pocket  expenses incurred by
each Agent and Bank, including (without  duplication) the fees and disbursements
of outside counsel and the allocated cost of inside counsel,  in connection with
such  Event  of  Default  and  collection,   bankruptcy,  insolvency  and  other
enforcement proceedings resulting therefrom.

                  (b) The  Borrower  agrees to  indemnify  each  Agent and Bank,
their respective affiliates and the respective directors,  officers,  agents and
employees  of the  foregoing  (each an  "Indemnitee")  and hold each  Indemnitee
harmless from and against any and all liabilities,  losses,  damages,  costs and
expenses of any kind,  including,  without  limitation,  the reasonable fees and
disbursements of counsel, which may be incurred by such Indemnitee in

                                       74





connection  with  any  investigative,   administrative  or  judicial  proceeding
(whether or not such Indemnitee  shall be designated a party thereto) brought or
threatened  relating  to or  arising  out of this  Agreement  or any  actual  or
proposed use of proceeds of Loans  hereunder;  provided that no Indemnitee shall
have the  right to be  indemnified  hereunder  for such  Indemnitee's  own gross
negligence  or  willful  misconduct  as  determined  by  a  court  of  competent
jurisdiction.

                  SECTION 9.4. Sharing of Set-Offs.  Each Bank agrees that if it
shall, by exercising any right of set-off or counterclaim or otherwise,  receive
payment of a proportion  of the  aggregate  amount of principal and interest due
with  respect  to any  Note  held by it  which is  greater  than the  proportion
received by any other Bank in respect of the  aggregate  amount of principal and
interest  due  with  respect  to any  Note  held by such  other  Bank,  the Bank
receiving   such   proportionately   greater   payment   shall   purchase   such
participations  in the Notes held by the other Banks, and such other adjustments
shall be made,  as may be required so that all such  payments of  principal  and
interest  with  respect  to the Notes  held by the Banks  shall be shared by the
Banks pro rata;  provided that nothing in this Section shall impair the right of
any Bank to  exercise  any right of set-off or  counterclaim  it may have and to
apply the amount subject to such exercise to the payment of  indebtedness of the
Borrower or the Parent Guarantor other than its indebtedness hereunder.  Each of
the  Borrower  and the Parent  Guarantor  agrees,  to the fullest  extent it may
effectively do so under  applicable law, that any holder of a participation in a
Note,  whether or not  acquired  pursuant  to the  foregoing  arrangements,  may
exercise rights of set-off or counterclaim and other rights with respect to such
participation  as  fully  as if such  holder  of a  participation  were a direct
creditor  of the  Borrower  or  the  Parent  Guarantor  in the  amount  of  such
participation.

                  SECTION 9.5.  Amendments  and Waivers.  Any  provision of this
Agreement or the Notes may be amended or waived if, but only if, such  amendment
or waiver is in writing and is signed by the  Borrower  and the  Required  Banks
(and, if the rights or duties of an Agent are affected thereby,  by such Agent);
provided  that (A) no such  amendment  or  waiver  shall,  unless  signed by the
Required  Release  Banks,  amend the  definition of Release Date and (B) no such
amendment  or waiver  shall,  unless  signed by all the Banks,  (i)  increase or
decrease  the  Commitment  of any Bank  (except  for a ratable  decrease  in the
Commitments of all Banks) or subject any Bank to any additional obligation, (ii)
reduce the principal of or rate of interest on any Loan, or any fees  hereunder,
(iii) postpone the date fixed for any payment of principal of or interest on any
Loan, or any fees hereunder or for any scheduled reduction or termination of any
Commitment,  (iv) change the aggregate  amount of Loans required to be repaid on
any  Principal  Repayment  Date,  (v)  release  the  Parent  Guarantor  from its
obligations  hereunder  or,  (vi)  release  all  or  substantially  all  of  the
Collateral or (vii) change the percentage of the Commitments or of the aggregate
unpaid  principal  amount of the Notes,  or the number of Banks,  which shall be
required  for the Banks or any of them to take any action  under this Section or
any other provision of this Agreement.

                                       75




                  SECTION 9.6.  Successors  and Assigns.  (a) The  provisions of
this  Agreement  shall be binding  upon and inure to the  benefit of the parties
hereto and their respective successors and assigns, except that the Borrower may
not assign or otherwise  transfer any of its rights under this Agreement without
the prior written consent of all Banks.

                  (b) Any  Bank may at any  time  grant to one or more  banks or
other  institutions  (each  a  "Participant")  participating  interests  in  its
Commitment or any or all of its Loans.  In the event of any such grant by a Bank
of a participating interest to a Participant,  whether or not upon notice to the
Borrower and the Agents,  such Bank shall remain responsible for the performance
of its obligations hereunder,  and the Borrower and the Agents shall continue to
deal solely and directly  with such Bank in  connection  with such Bank's rights
and obligations under this Agreement.  Any agreement  pursuant to which any Bank
may grant  such a  participating  interest  shall  provide  that such Bank shall
retain  the sole right and  responsibility  to enforce  the  obligations  of the
Borrower  hereunder  including,  without  limitation,  the right to approve  any
amendment,  modification or waiver of any provision of this Agreement;  provided
that such  participation  agreement may provide that such Bank will not agree to
any  modification,  amendment  or waiver of this  Agreement  described in clause
(B)(i), (B)(ii), (B)(iii), (B)(iv) or (B)(v) of Section 10.5 without the consent
of the  Participant.  The Borrower  agrees that each  Participant  shall, to the
extent provided in its participation  agreement,  be entitled to the benefits of
Article 8 with respect to its  participating  interest.  An  assignment or other
transfer  which is not permitted by  subsection  (c) or (d) below shall be given
effect for  purposes  of this  Agreement  only to the extent of a  participating
interest granted in accordance with this subsection (b).

                  (c) Any Bank may at any time, upon five Business Days' written
notice to each of the Agents, assign to one or more Eligible Assignees all, or a
proportionate  part  (equivalent  to an  initial  Commitment  of not  less  than
$5,000,000) of all, of its rights and  obligations  under this Agreement and the
Notes,  and such  Eligible  Assignee  shall assume such rights and  obligations,
pursuant to an Assignment and Assumption  Agreement in substantially the form of
Exhibit D hereto executed by such Eligible  Assignee and such  transferor  Bank,
with  (and  subject  to)  the  subscribed   consent  of  the  Borrower  and  the
Administrative  Agent,  which  consent  shall in each  case not be  unreasonably
withheld;  provided  that  if an  Eligible  Assignee  is an  affiliate  of  such
transferor  Bank or was a Bank  immediately  prior to such  assignment,  no such
consent shall be required.  Upon  execution and delivery of such  instrument and
payment by such Eligible  Assignee to such transferor Bank of an amount equal to
the  purchase  price  agreed  between  such  transferor  Bank and such  Eligible
Assignee,  such Eligible  Assignee  shall be a Bank party to this  Agreement and
shall have all the rights and  obligations  of a Bank with a  Commitment  as set
forth  in such  instrument  of  assumption,  and the  transferor  Bank  shall be
released  from its  obligations  hereunder  to a  corresponding  extent,  and no
further consent or action by any party shall be required. Upon the

                                       76





consummation  of any assignment  pursuant to this subsection (c), the transferor
Bank,  the  Administrative   Agent  and  the  Borrower  shall  make  appropriate
arrangements  so  that,  if  required,  a new  Note is  issued  to the  Eligible
Assignee,  and the  transferor  Bank shall provide prompt written notice of such
assignment to the  Documentation  Agent. In connection with any such assignment,
the transferor Bank shall pay to the Administrative  Agent an administrative fee
for processing such assignment in the amount of $2,500. If the Eligible Assignee
is not  incorporated  under the laws of the United  States of America or a state
thereof,  it  shall  deliver  to  the  Borrower  and  the  Administrative  Agent
certification as to exemption from deduction or withholding of any United States
federal income taxes in accordance with Section 8.4.

                  (d) Any Bank may at any time  assign all or any portion of its
rights under this  Agreement  and its Note to a Federal  Reserve  Bank.  No such
assignment shall release the transferor Bank from its obligations hereunder.

                  (e) No Eligible  Assignee,  Participant or other transferee of
any Bank's rights shall be entitled to receive any greater payment under Section
8.3 or 8.4 than such Bank would have been  entitled to receive  with  respect to
the rights  transferred,  unless such transfer is made with the Borrower's prior
written  consent  or by reason of the  provisions  of  Section  8.2,  8.3 or 8.4
requiring  such Bank to designate a different  Applicable  Lending  Office under
certain  circumstances or at a time when the  circumstances  giving rise to such
greater payment did not exist.

                  (f) At any time after the  occurrence  of a  Guarantor  Event,
each Bank shall, upon receipt from a Shareholder Guarantor of an amount equal to
its pro rata portion of all  Obligations to such Bank (the "Transfer  Payment"),
assign to such Shareholder  Guarantor a proportionate part (based on the portion
of the Transfer Payment owing to such Bank paid by such  Shareholder  Guarantor)
of its rights and  obligations  under this Agreement and the Notes in accordance
with  paragraph (c) of this Section  10.6;  provided that (i) the consent of the
Borrower and the Administrative  Agent shall not be required for such assignment
and (ii) no such assignment  shall be effective until each Bank has received its
Transfer Payment from the applicable Shareholder Guarantor.

                  SECTION 9.7.  Collateral.  Each of the Banks represents to
the Agents and each of the other Banks that it in good faith is not
relying upon any "margin stock" (as defined in Regulation U) as
collateral in the extension or maintenance of the credit provided for in
this Agreement.

                  SECTION 9.8. Governing Law;  Submission to Jurisdiction.  This
Agreement and each Note shall be governed by and  construed in  accordance  with
the laws of the State of New York. Each of the Borrower and the Parent Guarantor
hereby submits to the  nonexclusive  jurisdiction  of the United States District
Court for the Southern District of New York and of any New York State court

                                       77





sitting in New York City for purposes of all legal proceedings arising out of or
relating to this Agreement or the transactions  contemplated hereby. Each of the
Borrower and the Parent  Guarantor  irrevocably  waives,  to the fullest  extent
permitted by law, any objection which it may now or hereafter have to the laying
of the venue of any such  proceeding  brought in such a court and any claim that
any such proceeding  brought in such a court has been brought in an inconvenient
forum.

                  SECTION 9.9. Counterparts;  Integration;  Effectiveness.  This
Agreement may be signed in any number of counterparts, each of which shall be an
original, with the same effect as if the signatures thereto and hereto were upon
the same  instrument.  This  Agreement  constitutes  the  entire  agreement  and
understanding  among  the  parties  hereto  and  supersedes  any and  all  prior
agreements and understandings,  oral or written,  relating to the subject matter
hereof.  This Agreement shall become effective upon receipt by the Documentation
Agent of  counterparts  hereof signed by each of the parties  hereto (or, in the
case of any  party as to which  an  executed  counterpart  shall  not have  been
received,  receipt  by the  Documentation  Agent in form  satisfactory  to it of
telegraphic,  telex,  facsimile or other written confirmation from such party of
execution of a counterpart hereof by such party).

                  SECTION 9.10. WAIVER OF JURY TRIAL. EACH OF THE BORROWER,  THE
PARENT GUARANTOR, THE AGENTS AND THE BANKS HEREBY IRREVOCABLY WAIVES ANY AND ALL
RIGHT TO TRIAL BY JURY IN ANY LEGAL  PROCEEDING  ARISING  OUT OF OR  RELATING TO
THIS AGREEMENT OR THE TRANSACTIONS CONTEMPLATED HEREBY.

                  SECTION 9.11. Confidentiality. Each Bank agrees to take normal
and reasonable precautions and exercise due care to maintain the confidentiality
of all non-public  information  provided to it by the Parent Guarantor or any of
its  Subsidiaries by the Agents on the Parent  Guarantor's or such  Subsidiary's
behalf in connection with this Agreement or any Common  Collateral  Document and
neither  it nor any of its  Affiliates  shall use any such  information  for any
purpose or in any manner other than pursuant to the terms  contemplated  by this
Agreement,  except to the extent such  information (i) was or becomes  generally
available to the public other than as a result of a disclosure  by the Bank,  or
(ii) was or becomes  available on a  non-confidential  basis from a source other
than the Parent  Guarantor  or the  Borrower,  provided  that such source is not
bound by a  confidentiality  agreement with the Parent Guarantor or the Borrower
known  to  the  Bank;  provided,  further,  that  any  Bank  may  disclose  such
information  (A) to any other Bank or to the  Agents,  (B) at the request of any
Bank  regulatory  authority or in connection with an examination of such Bank by
any such  authority;  (C) pursuant to subpoena or other court process;  (D) when
required to do so in accordance  with the provisions of any applicable  law; (E)
at the express  direction of any other agency of any State of the United  States
of  America  or of any  other  jurisdiction  in which  such  Bank  conducts  its
business;  and  (F) to such  Bank's  independent  auditors  and  legal  counsel.
Notwithstanding  the foregoing,  the Company authorizes each Bank to disclose to
any Participant or Eligible Assignee (each, a "Transferee") and any prospective

                                       78





Transferee  such  financial  and other  information  in such  Bank's  possession
concerning  the  Parent  Guarantor  or any of its  Subsidiaries  which  has been
delivered to the Banks pursuant to this Agreement or which has been delivered to
the Banks by the Parent  Guarantor or any of its Subsidiaries in connection with
the Banks' credit evaluation of the Parent Guarantor and its Subsidiaries  prior
to entering into this Agreement; provided that such Transferee agrees in writing
to such Bank to keep such  information  confidential to the same extent required
of the Banks hereunder.

                                       79





                  IN WITNESS  WHEREOF,  the  parties  hereto  have  caused  this
Agreement to be duly executed by their respective  authorized officers as of the
day and year first above written.

                                               AMSC SUBSIDIARY CORPORATION


                                               By
                                                 --------------------
                                               Name: Richard J. Burnheimer
                                Title: Treasurer
                         Address: 10802 Parkridge Blvd.,
                                                         Reston, VA  22091
                                               Telex:
                             Facsimile: 703/716-6366


                                           AMERICAN MOBILE SATELLITE CORPORATION


                                                By
                                                  --------------------
                                                Name: Richard J. Burnheimer
                                Title: Treasurer
                         Address: 10802 Parkridge Blvd.,
                                                          Reston, VA  22091
                                                Telex:
                                                Facsimile: 703/716-6366




                                       80





Commitment


$75,000,000                                 TORONTO DOMINION (TEXAS), INC.


                                            By
                                               ---------------------------
                                            Name:
                                            Title:





$75,000,000                                 MORGAN GUARANTY TRUST COMPANY
                                                       OF NEW YORK


                                            By
                                               ---------------------------
                                            Name:
                                            Title:


Total Commitments
$150,000,000

                                       81






                                                  MORGAN GUARANTY TRUST COMPANY
                                                   OF NEW YORK, as Documentation
                                      Agent


                                                  By
                                                     -----------------------
                                                  Name:
                                                  Title:
                                    Address:
                                                  Telex:
                                   Facsimile:



                                                 TORONTO DOMINION (TEXAS), INC.,
                                                   as Administrative Agent


                                                 By
                                                    ------------------------
                                                 Name:
                                                 Title:
                                                 Address:
                                                 Telex:
                                   Facsimile:

                                       82





                   PRICING SCHEDULE PRIOR TO THE RELEASE DATE

             Each of "Euro-Dollar  Margin" and "Base Rate Margin" means, for any
date prior to the Release  Date,  the rates set forth below in the row  opposite
such term and in the column corresponding to the "Pricing Level" that applies at
such date:


                        Level        Level        Level         Level
                          I           II           III           IV
Euro-Dollar             0.25%        0.35%        0.45%         0.75%
Margin
Base Rate               0%           0%           0%            0%
 Margin
- -------------       -----------   ----------   ----------    ----------

                  For purposes of this  Schedule,  the following  terms have the
following meanings:

                  "Hughes Change in Control"  means General  Motors  Corporation
shall have  beneficial  ownership  of less than 51% of the  outstanding  capital
stock of Hughes.

                  "Level I Pricing"  applies  (x) prior to the  occurrence  of a
Hughes Change of Control or (y) upon or after the  occurrence of a Hughes Change
in Control if, as of such date, the Moody's Rating of Hughes is A3 or higher and
the S&P Rating of Hughes is A- or higher.

                  "Level  II  Pricing"  applies  at any date  upon or after  the
occurrence  of a Hughes  Change in Control if, as of such date,  (i) the Moody's
Rating of Hughes is Baa2 or higher and the S&P Rating of Hughes is BBB or higher
and (ii) Level I Pricing does not apply.

                  "Level  III  Pricing"  applies  at any date  upon or after the
occurrence  of a Hughes  Change in Control if, as of such date,  (i) the Moody's
Rating of Hughes is Baa3 and the S&P  Rating of Hughes is BBB- and (ii)  neither
Level I nor Level II Pricing applies.

                  "Level  IV  Pricing"  applies  at any date  upon or after  the
occurrence  of a Hughes  Change in Control if, as of such date, no other Pricing
Level applies.


                                       83






                  "Leveraged Lease Obligation" means the non-recourse obligation
of a trust or special  purpose  corporation  to repay notes issued by it to loan
participants,  which notes are issued to finance in part the  purchase  price of
equipment and secured by such  equipment and by the lease of such equipment to a
lessee,  where Hughes has  guaranteed  the financial  obligations  of the lessee
under the lease to the holders of the notes.

                  "Moody's" means Moody's Investors Service, Inc.

                  "Moody's  Rating" means, for any day, (i) if Hughes shall have
outstanding  any  publicly  traded  secured  debt that is rated by Moody's,  the
highest  rating of any such debt by  Moody's,  (ii) if clause (i) does not apply
and there shall be outstanding any Leveraged Lease Obligations that are rated by
Moody's,  the  highest  rating of any such  obligations  by Moody's and (iii) if
neither  clause (i) nor clause (ii)  applies,  the deemed rating of the Notes by
Moody's,  in each case as in effect at 9:00 a.m.,  New York City  time,  on such
day. If Moody's shall have changed its system of classifications  after the date
hereof,  the Moody's  Rating shall be  considered  to be at or above a specified
level if it is at or above the new rating which most closely  corresponds to the
specified level under the old rating system.

                  "Pricing Level" refers to the  determination of which of Level
I, Level II, Level III or Level IV applies at any date.

                  "S&P" means Standard & Poor's Rating Service.

                  "S&P  Rating"  means,  for any day,  (i) if Hughes  shall have
outstanding  any publicly  traded secured debt that is rated by S&P, the highest
rating  of any such  debt by S&P,  (ii) if  clause  (i) does not apply and there
shall be outstanding any Leveraged Lease  Obligations that are rated by S&P, the
highest  rating of any such  obligations  by S&P and (iii) if neither clause (i)
nor clause (ii) applies,  the deemed rating of the Notes by S&P, in each case as
in effect at 9:00  a.m.,  New York City  time,  on such day.  If S&P shall  have
changed  its system of  classifications  after the date  hereof,  the S&P Rating
shall be considered to be at or above a specified level if it is at or above the
new rating which most closely  corresponds to the specified  level under the old
rating system.


                                       84





                  PRICING SCHEDULE ON OR AFTER THE RELEASE DATE

                   Each of  "Euro-Dollar  Margin" and "Base Rate Margin"  means,
for any date on or after the Release Date,  the rates set forth below in the row
opposite such term and in the column  corresponding  to the "Pricing Level" that
applies at such date:



                   Level       Level      Level      Level     Level     Level
                     I          II         III        IV         V         VI
Euro-Dollar        1.25%       1.5%       1.75%      2.00%     2.50%     2.875%
Margin
Base Rate          0.25%       0.5%       0.75%      1.00%     1.50%     1.875%
 Margin
- --------------     ------      ------     ------     ------    ------    ------

                  For purposes of this  Schedule,  the following  terms have the
following meanings:

                  "Level I Pricing" applies at any date if, as of such date, the
Leverage Ratio is less than or equal to 2.0 to 1.

                  "Level II  Pricing"  applies  at any date if, as of such date,
(i) the  Leverage  Ratio is less  than or  equal  to 2.5 to 1 and  (ii)  Level I
Pricing does not apply.

                  "Level III  Pricing"  applies at any date if, as of such date,
(i) the Leverage  Ratio is less than or equal to 3.0 to 1 and (ii) neither Level
I Pricing nor Level II Pricing applies.

                  "Level IV  Pricing"  applies  at any date if, as of such date,
(i) the Leverage  Ratio is less than or equal to 3.5 to 1 and (ii) none of Level
I Pricing, Level II Pricing and Level III Pricing applies.

                  "Level V Pricing" applies at any date if, as of such date, (i)
the  Leverage  Ratio is less  than or equal to 4.0 to 1 and (ii) none of Level I
Pricing, Level II Pricing, Level III Pricing and Level IV Pricing applies.


                                       86





                  "Level VI Pricing" applies at any date if, as of such date, no
other Pricing Level applies.

                  "Leverage  Ratio"  means as of any date after the Release Date
the Leverage Ratio set forth in the most recent  certificate  delivered pursuant
to Section 5.2(c);  provided that unless the Required Banks otherwise  agree, if
the Borrower has failed to deliver the  financial  statements  and  accompanying
certificates  most  recently  required  to have been  delivered  within the time
periods  specified  therefor in Section 5.1,  Level VI Pricing shall apply until
the next date on which financial  statements and  accompanying  certificates are
timely delivered.

                  "Pricing Level" refers to the  determination of which of Level
I, Level II, Level III, Level IV, Level V or Level VI applies at any date.



                                       87





                              RELEASE DATE SCHEDULE


                  The  performance  tests  referred  to  in  the  definition  of
"Release  Date" will be met when the number of Subscribers as of the last day of
two  consecutive  three month periods  specified  below and Net Revenue for such
periods  shall not be less than the  number or amount,  respectively,  set forth
opposite  such periods  below and  Indebtedness  of the Parent  Guarantor  Group
divided by the number of  Subscribers  shall at no time during such periods have
exceeded the amount set forth opposite such periods.


                                                               Maximum
                                                               Indebtedness
                             Minimum          Minimum Net      per
Three Months Ending          Subscribers      Revenue          Subscriber

March 31, 1997                35,000          $12,500,000       $4,800
June 30, 1997                 46,000          $16,500,000       $3,800
September 30, 1997            58,000          $21,000,000       $3,000
December 31, 1997             70,000          $26,000,000       $2,600
======================       ============    =============    ================



                                       88





                                                               EXHIBIT A - Note



                                      NOTE



                                                             New York, New York
                                                                         , 199
                                                           ----------- --     -



                  For value received,  AMSC Subsidiary  Corporation,  a Delaware
corporation  dually  incorporated as a Virginia public service  corporation (the
"Borrower"), promises to pay to the order of (the
                                                    -----------------------
"Bank"),  for the account of its Applicable Lending Office, the unpaid principal
amount of each  Loan made by the Bank to the  Borrower  pursuant  to the  Credit
Agreement  referred to below on the  maturity  date  provided  for in the Credit
Agreement.  The Borrower promises to pay interest on the unpaid principal amount
of each  such Loan on the  dates  and at the rate or rates  provided  for in the
Credit  Agreement.  All such payments of principal and interest shall be made in
lawful  money of the United  States in Federal  or other  immediately  available
funds at the office of The Toronto-  Dominion  Bank,  31 West 52nd  Street,  New
York, New York.

                  All Loans made by the Bank, the  respective  types thereof and
all  repayments of the  principal  thereof shall be recorded by the Bank and, if
the Bank so  elects in  connection  with any  transfer  or  enforcement  hereof,
appropriate notations to evidence the foregoing information with respect to each
such Loan then outstanding may be endorsed by the Bank on the schedule  attached
hereto,  or on a  continuation  of such  schedule  attached  to and  made a part
hereof;  provided that the failure of the Bank to make any such  recordation  or
endorsement shall not affect the obligations of the Borrower  hereunder or under
the Credit Agreement.

                  This  note  is one  of the  Notes  referred  to in the  Credit
Agreement dated as of June 28, 1996 among AMSC Subsidiary Corporation,  American
Mobile Satellite

                                        1





Corporation, the banks party thereto, Morgan Guaranty Trust Company of New York,
as Documentation  Agent and Toronto  Dominion  (Texas),  Inc. as  Administrative
Agent (as the same may be amended  from time to time,  the "Credit  Agreement").
Terms defined in the Credit  Agreement  are used herein with the same  meanings.
Reference is made to the Credit  Agreement  for  provisions  for the  prepayment
hereof and the acceleration of the maturity hereof.

                  The payment in full of the principal and interest on this note
has,  pursuant to the provisions of the Credit Agreement,  been  unconditionally
guaranteed by American Mobile Satellite Corporation.


                                                     AMSC SUBSIDIARY CORPORATION




                                       By
                                                        -----------------------
                                      Name:
                                     Title:


                                        2






                         LOANS AND PAYMENTS OF PRINCIPAL


- --------------------------------------------------------------------------

                Amount      Type      Amount of
                  of         of       Principal     Notation
        Date     Loan       Loan       Repaid       Made By
- --------------------------------------------------------------------------

- --------------------------------------------------------------------------

- --------------------------------------------------------------------------

- --------------------------------------------------------------------------

- --------------------------------------------------------------------------

- --------------------------------------------------------------------------

- --------------------------------------------------------------------------

- --------------------------------------------------------------------------

- --------------------------------------------------------------------------

- --------------------------------------------------------------------------

- --------------------------------------------------------------------------

- --------------------------------------------------------------------------

- --------------------------------------------------------------------------

- --------------------------------------------------------------------------

- --------------------------------------------------------------------------

- --------------------------------------------------------------------------

- --------------------------------------------------------------------------



                                        3




- --------------------------------------------------------------------------

- --------------------------------------------------------------------------

                                        4





                EXHIBIT B-1 - Opinion of Counsel for the Borrower
                            and the Parent Guarantor




                                   OPINION OF
                COUNSEL FOR THE BORROWER AND THE PARENT GUARANTOR


                                                              June 28,  1996


To the Banks, Shareholder Guarantors and the Agents
  Referred to Below
c/o Morgan Guaranty Trust Company
  of New York, as Documentation Agent
60 Wall Street
New York, New York  10260

Dear Sirs:

                  I am Vice  President,  Secretary  and General  Counsel of AMSC
Subsidiary Corporation, a Delaware corporation dually incorporated as a Virginia
public service  corporation  (the  "Borrower"),  and American  Mobile  Satellite
corporation, a Delaware Corporation (the "Parent Guarantor"). In such capacity I
have become  familiar with the following  agreements,  each of which is dated of
even  date  herewith:   (i)  the  $150,000,000  Credit  Agreement  (the  "Credit
Agreement") among the Borrower,  the Parent  Guarantor,  the banks listed on the
signature  pages  thereof,  Morgan  Guaranty  Trust  Company  of  New  York,  as
Documentation Agent and Toronto Dominion (Texas),  Inc., as Administrative Agent
and (ii) the $75,000,000  Credit  Agreement (the "Revolving  Credit  Agreement")
among the  Borrower,  the Parent  Guarantor,  the banks listed on the  signature
pages thereof, Morgan Guaranty Trust Company of New York, as Documentation Agent
and Toronto Dominion (Texas),  Inc. as Administrative  Agent.  Capitalized terms
not  otherwise  defined  herein  shall have the meanings set forth in the Credit
Agreement,  the Revolving Credit Agreement or the Intercreditor  Agreement ("the
Intercreditor  Agreement"),  the Security Agreement (the "Security  Agreement"),
the Amended and Restated Continuing Guaranty dated as of March 15, 1995, between
the Borrower and the Common Collateral Agent (the "Continuing Guaranty")

                                        1





or the Parent Pledge  Agreement (the "Parent Pledge  Agreement")  referred to in
the definition of "Common  Collateral" in the Credit Agreement,  as the case may
be and as the  context  may  require.  This  opinion  is being  rendered  to you
pursuant to Section  3.1(a) of the Credit  Agreement  and Section  3.1(a) of the
Revolving Credit Agreement.

                  In rendering this opinion, I have examined originals or copies
of:

                  (i)  the Credit Agreement and the Revolving Credit
         Agreement;

                  (ii)  the Intercreditor Agreement, the Security
         Agreement, the Parent Pledge Agreement and the Continuing
         Guaranty;

                  (iii)  the   financing   statements  on  Form  UCC-1  and  the
         amendments  to financing  statements of Form UCC-3  attached  hereto as
         Exhibits A and B (the "Financing Statements");

                  (iv) the  Security  Agreement  dated as of  August  31,  1992,
         between the  Borrower  and Bank of America  National  Trust and Savings
         Association,  as agent, and the Security Agreement dated as of February
         2, 1993,  between the Borrower and  Westinghouse  Electric  Corporation
         ("Westinghouse") (the "Original Security Agreements");

                  (v)  the certificates of incorporation, as amended,
         of the Borrower and of the Parent Guarantor;

                  (vi)  the bylaws, as amended, of the Borrower and of
         the Parent Guarantor;

                  (vii) the  Certificates  of Good  Standing with respect to the
         Borrower and the Parent  Guarantor  issued by the Secretary of State of
         the State of Delaware dated June 18 and 19, 1996 respectively;

                  (viii) the  Certificate  of Good  Standing with respect to the
         Borrower issued by the State Corporation Commission of the Commonwealth
         of Virginia dated June 19, 1996;

                                        2





                  (ix) the Certificate of Good Standing as a Foreign Corporation
         with respect to the Parent  Guarantor  issued by the State  Corporation
         Commission of the Commonwealth of Virginia dated June 19, 1996;

                  (x)  certain resolutions adopted by the Board of
         Directors of the Borrower at a meeting of the Board held
         on June 27, 1996; and

                  (xi) certain  resolutions adopted by the Board of Directors of
         Parent Guarantor at a meeting of the Board held on June 27, 1996;

upon all of which I have relied. I have not  independently  verified any factual
matters in connection with or apart from my review of the documents  referred to
above and,  accordingly,  I do not express any opinion as to matters  that might
have been disclosed by independent verification.

                  In arriving at the opinions  expressed  below, I have assumed,
and not verified, the authenticity of all documents submitted to me as originals
and the  conformity to original  documents of all  documents  submitted to me as
copies,  as well as the due and valid  authorization,  execution and delivery of
all such documents by the  appropriate  party or parties (other than the due and
valid  authorization,  execution  and  delivery by the  Borrower  and the Parent
Guarantor),  and that each such  party  other  than the  Borrower  or the Parent
Guarantor, as applicable, has adequate power, authority and legal right to enter
into such documents to which it is a party and to perform its obligations  under
such documents to which it is a party.

                  Based solely upon the foregoing and in reliance  thereon,  and
subject to the qualifications,  limitations and assumptions set forth herein, it
is my opinion that:

                  1.  Each  of  the  Borrower  and  the  Parent  Guarantor  is a
corporation duly  incorporated,  validly existing and in good standing under the
laws of Delaware and, in the case of the  Borrower,  under the laws of Virginia,
has all corporate powers and all material governmental licenses, authorizations,
consents and approvals  required to carry on its business as now conducted,  and
is duly qualified as a foreign corporation, licensed and in good standing

                                        3





under the laws of each jurisdiction  where its ownership,  lease or operation of
property or the conduct of its business require such qualification  except where
the failure to be so qualified  would not  reasonably be expected to result in a
Material Adverse Effect.

                  2. The execution,  delivery and performance by the Borrower of
the Credit Agreement,  the Revolving Credit Agreement,  the Notes, the Notice of
Amount of Secured  Obligations  and the Notice of New  Secured  Party and by the
Parent Guarantor of the Credit Agreement, the Revolving Credit Agreement and the
Notice of New Secured Party are within the  corporate  powers of the Borrower or
Parent  Guarantor,  as  relevant,  have been duly  authorized  by all  necessary
corporate  action  and do not and will  not:  (a)  contravene  the terms of such
Person's certificate of incorporation,  bylaws or other organization  documents;
(b) conflict with or result in any breach or  contravention  of, or the creation
of any Lien under,  any indenture,  agreement,  lease,  instrument,  Contractual
Obligation,  injunction,  order, decree or undertaking to which such Person is a
party (other than Liens under the Common Collateral  Documents);  or (c) violate
any Requirement of Law.

                  3. The Credit  Agreement,  the Revolving  Credit Agreement and
each  other  Loan  Document  to  which  the  Parent  Guarantor  or  any  of  its
Subsidiaries is a party constitute the legal,  valid and binding  obligations of
such Person, enforceable against such Person in accordance with their respective
terms.

                  4.  Except  as set  forth  in  Section  4.5 of the  Disclosure
Schedule  and for  matters  arising  after the  Effective  Date which  could not
reasonably be expected to have a Material Adverse Effect,  there are no actions,
suits, proceedings, claims or disputes pending, or to the best of our knowledge,
threatened  or  contemplated  at law, in equity,  in  arbitration  or before any
Governmental Authority,  against the Parent Guarantor or any of its Subsidiaries
or any of their respective properties which: (a) purport to affect or pertain to
the Credit  Agreement,  the Revolving Credit Agreement or any Loan Document,  or
any of the transactions  contemplated thereby; or (b) if determined adversely to
the Parent Guarantor or any of its Subsidiaries, could have a Material

                                        4





Adverse Effect. No injunction, writ, temporary restraining order or any order of
any  nature  has  been  issued  by any  court or  other  Governmental  Authority
purporting to enjoin or restrain the execution,  delivery and performance of the
Credit Agreement,  the Revolving Credit Agreement or any other Loan Document, or
directing  that the  transactions  provided  for therein not be  consummated  as
therein provided.

                  5. None of the Borrower,  any Person controlling the Borrower,
or any Subsidiary thereof, is (a) an "Investment  Company" within the meaning of
the  Investment  Company  Act of 1940;  or (b) subject to  regulation  under the
Public  Utility  Holding  Company Act of 1935, or, to the best of our knowledge,
the Federal Power Act, the Interstate  Commerce Act, any state public  utilities
code or any other Federal or state statute or regulation limiting its ability to
incur Indebtedness.

                  6. The  Common  Collateral  Documents  create  in favor of the
Common  Collateral  Agent, for the benefit of the Secured  Parties,  a valid and
enforceable Lien on the Common Collateral,  securing the payment and performance
of all Secured  Obligations,  and the security  interest  granted in such Common
Collateral under the Common Collateral Documents constitutes a perfected lien on
such Common  Collateral  with respect to types of items of Collateral in which a
security  interest  may be  perfected  by the filing in  Virginia of a financing
statement  under  Article 9 of the  Uniform  Commercial  Code of  Virginia as in
effect on the date hereof (the "Applicable Code"), subject to the following:

                  (a) in case of proceeds,  perfection and the  continuation  of
perfection of the Common Collateral  Agent's security interest is limited to the
extent set forth in Section 9-306 of the Applicable Code;

                  (b) in the case of property  which  becomes part of the Common
Collateral  after the date hereof,  Section 552 of the United States  Bankruptcy
Code,  11 U.S.C.  ss.  101 et seq.  (as  amended),  limits  the  extent to which
property acquired by a debtor after the commencement of a case under the federal
bankruptcy  laws may be subject to a security  interest  arising from a security
agreement entered into by the debtor before the commencement of such a case;

                                        5







                  (c) in  case  of the  Pledged  Collateral,  perfection  of the
security  interest may require transfer of possession of the Pledged  Collateral
to the  Common  Collateral  Agent or a person  designated  by it as set forth in
Section 8-313 of the Applicable Code;

                  (d) in the case of Rolling Stock consisting of motor vehicles,
perfection  of the  security  interest  in any such motor  vehicle  may  require
notation of such security  interest on the certificate of title relating to such
motor vehicle;

                  (e)  perfection  of  the  security  interest   generally  will
terminate  under  the  circumstances   described  in  Section  9-103  (relating,
generally,  to perfection of security  interests in multiple-state  transactions
and the effect of the change of location of the  collateral  or the debtor),  9-
402 (relating,  generally to the formal  requisites of financing  statements and
the effect of changes in the debtor's name, identity or corporate structure) and
9-403 (relating, generally, to the duration (five years) of the effectiveness of
a filing and the filing of  continuation  statements)  of the  Applicable  Code,
unless appropriate action is taken as provided therein; and

                  (f)  the  Common  Collateral  Documents  will  create  such  a
security interest in property in which the Borrower or the Parent Guarantor have
no present  rights only when the Borrower or the Parent  Guarantor,  as the case
may be acquires rights therein.

                  The Agents and the Banks are Secured Parties and the
Obligations are Secured Obligations.

                  In giving the opinions  set forth in this  paragraph 6, I have
assumed  without  investigation  that the Original  Security  Agreements and the
Original Pledge Agreement create a security interest in favor of Bank of America
National Trust and Savings association,  as agent ("BofA"), or Westinghouse,  as
the case may be, under  Article 9 of the  Applicable  Code,  as security for the
obligations of the Borrower under the Credit Agreement dated as of August 31,

                                        6





1992, by and among the Borrower,  the banks signatory  thereto and BofA, and the
Deferred Payment Agreement  between the Borrower and  Westinghouse,  dated as of
September  15,  1992,  in the  Borrower's  rights,  title  and  interest  in the
collateral  described  in  the  Original  Security  Agreements  and  the  Parent
Guarantor's  right,  title  and  interest  in the  collateral  described  in the
Original Pledge Agreement, and that financing statements in the proper form have
been  filed  and  such  filings  perfecting  the  security  interest  of BofA or
Westinghouse, as the case may be, in the collateral described therein and in the
Original  Security  Agreements.  The opinions set forth in this  paragraph 6 are
subject to further qualification that I express no opinion as to:

                  (i)  the Borrower's rights in or title to any Common
         Collateral;

                  (ii)  the priority of the Common Collateral Agent's
         security interest in the Common Collateral;

                  (iii)  the validity or perfection of the Common
         Collateral Agent's security interest in the Satellite;

                  (iv) the  validity  or  perfection  of the  Common  Collateral
         Agent's   security   interest  in  any  interest  of  the  Borrower  in
         copyrights,  patents, patent applications,  trademarks,  service marks,
         trademark  and service mark  applications,  and all other  intellectual
         property  protected or protectable  under the Federal law of the United
         States;

                  (v)  the  validity  or  perfection  of the  Common  Collateral
         Agent's security interest in any policy of insurance  maintained by the
         Borrower  except to the  extent  that  amounts  payable  under any such
         policy of  insurance  constitute  proceeds of Common  Collateral  under
         Section 9- 306(1) of the Applicable Code;

                  (vi) the validity or  perfection  of the security  interest in
         any Common  Collateral  consisting of deposit accounts (as such term is
         defined in the  Applicable  Code) except to the extent any such deposit
         account constitutes cash proceeds under Section 9-306 of the Applicable
         Code;


                                        7





                  (vii) the validity or perfection  of the security  interest in
         any Common Collateral sold, exchanged,  leased or otherwise disposed of
         by the Borrower in the ordinary course of business, as permitted by the
         Security  Agreement  or with the  consent,  express or implied,  of the
         Common Collateral Agent;

                  (viii) the  effectiveness  of the security  interest in Common
         Collateral  sold by the Borrower to a "buyer in the ordinary  course of
         business" within the meaning of Section 9-307(1) of the Applicable Code
         under   circumstances  not  permitted  by  the  Security  Agreement  or
         otherwise  without  the  consent,  express  or  implied,  of the Common
         Collateral Agent;

                  (ix) the  effectiveness  of the  security  interest  to secure
         loans,  advances or other  extensions of credit,  as against  buyers of
         Common  Collateral  from the  Company  otherwise  than in the  ordinary
         course of  business,  made to the Borrower  subsequent  to the time the
         Common  Collateral  Agent acquires  knowledge of the purchase,  or more
         than 45 days after the date of such purchase,  whichever  occurs first,
         and not made pursuant to a commitment entered into without knowledge of
         such  purchase and before the  expiration  of 45 days after the date of
         such purchase;

                  (x) the validity or perfection of the security  interest as to
         any  Common  Collateral  consisting  of goods  which  are  subsequently
         commingled with like goods or  manufactured,  processed or assembled so
         as to lose their identity in the mass, as against another secured party
         having a security interest in goods comprising part of the mass, except
         that in such  circumstances,  the security  interest in such goods will
         attach to the mass under Section 9-315 of the Applicable  Code and rank
         equally with other perfected  security  interests in the mass according
         to the ratio that the costs of the goods to which the security interest
         originally attached bears to the cost of the total mass; and

                  (xi)  (A)  the  enforceability  of  provisions  in the  Common
         Collateral  Documents as to self-help and  non-judicial  remedies,  (B)
         whether the procedures relating to the sale or disposition of the

                                        8





         Common  Collateral  in  the  Common  Collateral  Documents  would  meet
         applicable requirements for a commercially reasonable disposition,  and
         (C) the  enforceability  of the  provisions  in the  Common  Collateral
         Documents  relating  to or  purporting  to limit the Common  Collateral
         Agent's duty with respect to the Common Collateral.

                  The   foregoing   opinions   are  subject  to  the   following
assumptions and qualifications:

                  (a) The opinions  set forth in  paragraphs 3 and 6 are subject
to  the  effect  of  any  applicable  bankruptcy,  insolvency,   reorganization,
moratorium  or similar laws  affecting  creditors'  rights  generally and to the
possible judicial  application of foreign laws or governmental  action affecting
the enforcement of creditors' rights.

                  (b) The opinions  set forth in  paragraphs 3 and 6 are subject
to the further  qualification  that the enforceability of the obligations of the
Borrower and the Parent  Guarantor under the Credit  Agreement and the Revolving
Credit are subject to general  principles of equity  (regardless of whether such
enforceability  is  considered  in a  proceeding  in  equity  or at  law).  Such
principles  of  equity  are  of  general   application  and,  in  applying  such
principles,  a  court,  among  other  things,  might  not  allow a  creditor  to
accelerate  the  maturity  of a debt upon the  occurrence  of a  default  deemed
immaterial  or might  decline  to  order  that a  covenant  be  performed.  Such
principles  applied by a court might include,  among other things, a requirement
that creditors act with  reasonableness and good faith. Such a requirement might
be  applied,  among other  situations,  to the  provisions  of either the Credit
Agreement  or  the  Revolving  Credit  Agreement  requiring  the  payment  of an
indemnity  or  compensation  to any party  thereto or  purporting  to  authorize
conclusive determinations by any party thereto.

                  (c) Without  limiting the foregoing,  I call to your attention
certain exceptions noted below.

                  (i) With respect to my opinion in paragraph 3
hereof, I express no opinion as to whether the courts of a

                                        9





jurisdiction other than the State of New York would give effect to the choice of
New York law as  governing  the  agreements  as to which I express an opinion in
paragraph 3.

                 (ii) With respect to my opinion in paragraph 3
hereof,

                           (A) No  opinion  is  expressed  with  respect  to the
                  enforceability  of any  provision  in  Article 9 of the Credit
                  Agreement  or  Article  9 of the  Revolving  Credit  Agreement
                  purporting to guarantee the liability of the Borrower  despite
                  the  fact   that  the   obligations   being   guaranteed   are
                  unenforceable  due to  illegality  or the fact that any one of
                  the  Agents or any one of the Banks had  voluntarily  released
                  the  primary   obligor's   liability   with  respect  to  such
                  guaranteed obligations.

                           (B)  Section  9.2(ii)  of the  Credit  Agreement  and
                  Section  9.2(ii)  of the  Revolving  Credit  Agreement,  which
                  provide that the liability of the Parent  Guarantor  shall not
                  be affected by certain changes,  modifications,  amendments or
                  waivers referred to therein,  might be enforceable only to the
                  extent that such changes, modifications, amendments or waivers
                  were not so material as to constitute a new contract among the
                  parties.

                           (C) I express no opinion as to the  enforceability of
                  Section  9.4 of the Credit  Agreement  and  Section 9.4 of the
                  Revolving Credit Agreement insofar as either of them relate to
                  any  waiver or  extension  of or  agreement  not to assert any
                  defense based upon an applicable statue of limitations.

                  (d) The  foregoing  opinions  are  limited  to the laws of the
State of New York,  the General  Corporation  Law of the State of Delaware,  the
laws of the  Commonwealth  of Virginia and the Federal law of the United  States
(except as noted below),  and I do not express any opinion herein concerning any
other law (including, without limitation, any such other law of any jurisdiction
wherein any party to any of the Credit Agreement, the Revolving Credit Agreement
or any

                                       10





other Loan Document may be located or deemed  located or wherein  enforcement of
any such  documents  may be  sought).  I do not  express  any  opinion as to any
matters arising under the Communications  Act of 1934, as amended,  or any rules
or regulations of the Federal  Communications  Commission.  I do not express any
opinion  as to  any  matters  (including  Governmental  Approvals)  relating  to
international law, including compliance by the Borrower and the Parent Guarantor
with treaties involving the International Maritime Satellite  Organization,  the
International  Telecommunications  Satellite  Organization and the International
Telecommunication  Union.  I am not a member of the Bar of the State of Delaware
and insofar as the opinions  expressed  herein  relate to matters of the General
Corporation  Law of the State of Delaware,  I have relied on the latest standard
compilations of statutes available to me.

                  The  opinions  herein  are  rendered  as of the  date  of this
opinion,  and I assume no obligation to revise or supplement this opinion at any
date subsequent hereto.

                  The opinions  set forth above relate  solely to the matters as
to which my opinion has been  requested by you,  and you must judge  whether the
matters addressed herein are sufficient for your purposes.  I do not express any
opinion as to any other matters.

                  This  opinion is  rendered to the  Documentation  Agent and is
solely for its benefit, for the benefit of the Shareholder  Guarantors,  and for
the benefit of any Bank party to the Credit  Agreement or the  Revolving  Credit
Agreement  in  connection  with the above  transaction.  This opinion may not be
relied upon by the Documentation  Agent for any other purpose,  or furnished to,
quoted to or relied upon by any other Person other than any Bank  referred to in
the  immediately  preceding  sentence,  for any purpose without my prior written
consent.  It is not to be filed with or furnished to any Governmental  Authority
or other Person in either case without my prior written consent.

                                Very truly yours,



                                 Randy S. Segal
                                 General Counsel

                                       11








              EXHIBIT B-2 - Opinion of FCC Counsel to the Borrower
                            and the Parent Guarantor






                                                              June 28, 1996



The Banks and the Agents
       Referred to Below
c/o Morgan Guaranty Trust Company
       of New York, as Documentation Agent
60 Wall Street
New York, New York  10260

                  Re:  American Mobile Satellite Corporation

Ladies and Gentlemen:

                  We have acted as special  communications  counsel for American
Mobile  Satellite  Corporation  (the "Parent") and AMSC  Subsidiary  Corporation
("AMSC") with respect to the authorization issued to AMSC (the "License") by the
Federal  Communications  Commission  (the  "FCC")  as  described  more  fully in
Attachment I appended  hereto (the  "License").  This opinion is being delivered
pursuant to Section 3.1(a)(xiv)(y) of the $150,000,000 Credit Agreement dated as
of June 28, 1996 among AMSC,  Parent,  the Banks listed on the  signature  pages
thereof,  Morgan Guaranty Trust Company of New York, as Documentation Agent, and
Toronto  Dominion   (Texas),   Inc.,  as   Administrative   Agent  (the  "Credit
Agreement").

                  In  rendering  this  opinion,  we are  engaged  and  acting as
counsel  solely for the Parent and AMSC,  and are  delivering our opinion to you
solely in that  capacity.  This opinion is limited  strictly to matters  arising
under the  Communications  Act of 1934,  as amended,  and the  published  rules,
regulations,  and policies promulgated thereunder by the FCC (collectively,  the
"Communications   Laws"),  and  we  express  no  opinion  on  any  other  matter
whatsoever. Specifically excluded from this opinion are all matters relating to

                                        1





international  law,  including  compliance  by the Parent and AMSC with treaties
involving Inmarsat, Intelsat, and the International Telecommunication Union.

                  This  opinion is limited to those  aspects of the  business of
AMSC that  relate to the first  satellite  that AMSC has  launched  and plans to
operate.  As a satellite  communications  company that uses the radio  frequency
spectrum  and is a common  carrier,  AMSC is  subject  to  extensive  regulation
generally  pursuant  to the  Communications  Laws and  specifically  pursuant to
certain  orders of the FCC,  including  Report and Order, 2 FCC Rcd 1825 (1987),
recon.  denied  Memorandum  Opinion and Order,  2 FCC Rcd 6830  (1987),  further
recon.  denied  Memorandum  Opinion  and Order,  4 FCC Rcd 6016  (1989);  Second
Memorandum  Opinion and Order, 2 FCC Rcd 485 (1986);  recon.  denied  Memorandum
Opinion  and  Order,  4  FCC  Rcd  6029  (1989);  Memorandum  Opinion,  Order  &
Authorization,  4 FCC Rcd 6042 (1989);  Final Decision on Remand,  7 FCC Rcd 266
(1992);  Report and Order, 4 FCC Rcd 6072 (1989). These laws and regulations and
their interpretation by the FCC and the courts are subject to change over time.

                  We have  undertaken no inspection  whatsoever of the Parent or
AMSC,  their  affiliates,  or the  properties  of the  Parent  of AMSC or  their
affiliates,  and, except for our examination of records routinely  available for
public  inspection at the FCC and of our internal  files  pertaining to AMSC, we
have undertaken no independent  factual inquiry whatsoever of any of the matters
addressed  in this  opinion;  provided,  however,  that  insofar as this opinion
addresses,  is  affected  by, or  pertains  to the alien  ownership  or  control
restrictions under the  Communications  Laws or to alien ownership in the Parent
or AMSC,  we are  relying  solely on factual  information  provided to us by the
Parent on November  6, 1995 and June 25,  1996,  a summary  analysis of which is
attached  hereto as  Attachment  II (the  "Alien  Ownership  Analysis")  and the
following assumptions:

         3.       The information provided to us by the Parent for
                  the Alien Ownership Analysis is accurate in all
                  material respects as of the date hereof;

         4.       The Parent wholly owns AMSC;

                                        2





         5.       The information provided to us by the Parent as to
                  the identity and citizenship of all directors and
                  officers of each of the Parent and AMSC is
                  accurate as of the date hereof;

         6.       The shareholders of the Parent exercise collective
                  ultimate control over the Parent and AMSC through
                  the pro rata exercise of their voting rights based
                  upon the total number of shares in the Parent that
                  they each hold, that no individual shareholder of
                  Parent exercises actual or de facto control over
                  the Parent or AMSC, and, except for the Amended
                  and Restated Stockholders' Agreement dated as of
                  December 1, 1993, by and among the Parent and the
                  signatories thereto, there exists no voting
                  trust(s), agreement(s), or arrangement(s) among or
                  between any or all of shareholders that alter the
                  pro rata exercise of voting rights and control of
                  the Parent and AMSC.

                  In  rendering   this   opinion,   we  have   assumed   without
investigation  the  genuineness  of all  signatures,  the legal  capacity of all
natural persons,  the  authenticity of all documents  examined by us, whether or
not they are originals,  the conformity of all unexecuted documents presented to
us as  final  versions  thereof  to the  executed  originals  of the  same,  the
conformity  of all copies of  facsimile  transmissions  to the  originals of the
same,  whether or not they are certified to be true copies, and the accuracy and
completeness  of all public  records,  including but not limited to those of the
FCC.  The  opinions  expressed in this letter are based upon the current law and
facts  presently  known to us, and are not guarantees or assurances of any fact,
event,  occurrence,  omission,  or  condition  or of  any  law,  statute,  rule,
regulation,  policy,  order,  case,  or  interpretation  of the same.  When used
herein, "or" shall mean "and/or" unless the context otherwise requires.

                  The  Attachments  hereto  constitute  a material  part of this
opinion and should be viewed accordingly.

                  Based upon the  foregoing  and subject in all  respects to the
qualifications  and limitations set forth in this letter,  we are of the opinion
that:

                                        3





                  7.  Subject  to the  terms  and  conditions  set  forth in the
License Order described in Attachment I and to the  qualifications  described in
Attachment I, (i) AMSC has been  authorized by the FCC to construct,  launch and
operate a mobile  satellite  system  and offer,  on a common  carrier  basis,  a
variety  of  domestic  mobile  satellite  communications   services,   including
aeronautical,  maritime,  and land mobile services pursuant to the License, (ii)
the FCC has  assigned  AMSC use of the orbit  location at 101 degrees  W.L.  for
AMSC's  first  satellite  and has  authorized  AMSC,  subject  to  international
frequency  coordination,  to use frequency  bands 1544 to 1559 MHz and 1645.5 to
1660.5 MHz to provide the authorized mobile satellite services. The license term
for the AMSC satellite is ten years, beginning on August 21, 1995.

                  8.  Except  as  set  forth  in  Attachment  I and  except  for
rulemaking  proceedings  or  similar  proceedings  of general  applicability  to
entities such as the Parent or AMSC, to the best of our knowledge,  (i) there is
no  investigation,  action or  proceeding  (including  any  notice  of  apparent
liability or order of forfeiture) pending, threatened or outstanding against the
Parent or AMSC,  before the FCC, which seeks, or may reasonably be expected,  to
rescind,  terminate,  materially  adversely modify, or suspend the License,  and
(ii) the License is in full force and effect.

                  9. The grant by AMSC of a security interest in the proceeds of
any sale of the  License  as  contemplated  by Section  3.1(a)(x)  of the Credit
Agreement  would not violate or contravene (i) the  Communications  Laws or (ii)
any FCC permit,  authorization,  license  (including the License),  franchise or
approval granted to or held by AMSC.

                  This  opinion  may be  relied  upon by you (and any  permitted
assignee  of the Loans or the  Commitments  (as such  terms are  defined  in the
Credit Agreement)) in connection with the Credit Agreement,  is not to be relied
upon by any other person or entity for any reason  whatsoever,  and is not to be
quoted in whole or in part or otherwise  referred to in any  document  except as
directly a part of and related to the Credit Agreement.  In addition,  except as
otherwise  required by  applicable  law, this opinion is not to be filed with or
provided to any government agency or any other entity or person whatsoever.

                                        4





Finally,  this opinion addresses matters only as of the date of this opinion and
we  specifically  disclaim  any  responsibility  for  advising you of changes in
matters addressed herein occurring after such date.

                                        Very truly yours,

                         FISHER WAYLAND COOPER LEADER &
                                ZARAGOZA, L.L.P.


Attachments

                                        5






                                  ATTACHMENT I

                  In 1989, the Federal  Communications  Commission issued to the
Parent a license to  construct,  launch and  operate a mobile  satellite  system
subject to certain terms and conditions described in its orders.  License Order,
4 FCC Rcd 6041, Final Decision on Remand,  7 FCC Rcd 266 (1992);  aff'd sub nom.
Aeronautical  Radio,  Inc. v. FCC,  983 F.2d 75 (1993);  Memorandum  Opinion and
Order, 8 FCC Rcd 4040 (1993). In response to applications by the Parent, the FCC
authorized the assignment of the License to AMSC. Order and Authorization,  File
No. 13-DSS-AL-91(3) (March 22, 1991).

                  The FCC authorized  AMSC to construct  AMSC-1 to be capable of
operation in the  1530-1544/1630-1645.5 MHz bands. Memorandum Opinion and Order,
8 FCC Rcd 4040 (1993).

                  The  FCC  granted  AMSC  authority  under  Section  214 of the
Communications  Act to  operate as an  international  resale  carrier  (File No.
ITC-95-196)(1995)  and to lease a limited  amount of  satellite  capacity to TMI
Communications  and Company for provisions of mobile satellite service in Canada
(File No.  ITC-95-306).  The FCC also has granted AMSC Section 214  authority to
provide  incidental   transborder  and  international  maritime  service  within
coverage  area of the  AMSC-1  satellite  (File No.  ITC-95-28U).  AMSC also has
pending  before the FCC an  application  for  Section 214  authority  to provide
incidental  transborder  and  international   aeronautical  service  within  the
coverage area of AMSC-1 satellite (File No. ITC-95-626).

                  AMSC holds several  licenses for the operation of mobile earth
terminals using the AMSC-1 space segment.

         (a)  Blanket authority to construct and operate up to 200,000 mobile
         voice terminals for operation in the 1545-1559/1646.5-1660 MHz bands.
         Call Sign E930367, File No. 2823-DSE-P/L-93 (March 13, 1995).


                  An application for review of AMSC's blanket  authorization was
         filed by TRW,  Inc.,  on April 12, 1995,  in which TRW raised  concerns
         regarding  the  impact of this grant on future  licensing  in the 1525-
         1544/1630-1645.5  MHz bands.  This matter is still  pending  before the
         FCC.  AMSC filed a petition  for  partial  reconsideration  challenging
         certain FCC findings  regarding the radiation hazard analysis submitted
         with its blanket voice mobile terminal application. This matter is also
         still pending.

         (b)  Authority to modify its blanket voice mobile  terminal  license in
         order  to  add  certain  modified  emissions  standards,   and  to  add
         specifications for several different mobile, fixed and maritime antenna
         models. File Nos. 894-DSE-MP/L-95;  1034-DSE-MP/L-95 (August 28, 1995).
         In  granting  these  modifications,   the  Commission  imposed  certain
         obligations  on AMSC  regarding  the  mounting of its  antennas and the
         attachment  of warning  labels to  minimize  public  exposure to energy
         radiated by the antennas.

                  On March 15,  1996,  AMSC filed an  application  to modify its
         voice terminal authorization to add a new model high gain antenna. File
         No.  789-DSE-MP/L-96.  That application is unopposed.  AMSC anticipates
         that additional applications for modification of its authorizations may
         be  filed  to add  additional  antenna  models,  as the  need  for such
         antennas is identified.

         (c)  Blanket  authority  to  operate  up to 30,000  data  mobile  earth
         terminals  using  AMSC-1 space  segment.  Call Sign  E900081,  File No.
         681-DSE-MP/L-95  (August 1, 1995).  The FCC limited  operations  in the
         1545-  1559/1646.5-1660  MHz band to full-duplex  terminals  capable of
         transmitting  and  receiving  messages at the same time,  which the FCC
         found to be necessary in order to fulfill the  requirements  to provide
         real-time  priority and preemptive  access for aeronautical  safety and
         distress  communications  in these bands.  The FCC granted AMSC special
         temporary  authority  to  operate  up to 3,100  half-duplex  terminals,
         capable  of  communicating  in only  one  direction  at a time,  in the
         1530-1544/1630-1645.5 MHz bands, along with a waiver of the requirement
         to provide real-time priority and preemptive access for maritime safety
         services  in these  bands as set forth in  Footnote  US315 of the FCC's
         Table of Frequency Allocations, for a period of two years

                                        1





         until August 1, 1997.  On August 4, 1995,  the FCC increased the number
         of terminals  authorized  to operate in the  1530-1544/1630-1645.5  MHz
         band by 12,000.  Applications for extension of this authority have been
         granted by the FCC. This current authority expires on October 25, 1996.
         The FCC has proposed to grant AMSC permanent  authority to operate half
         duplex  terminals  in these  bands,  subject to  certain  restrictions.
         Notice of Proposed Rulemaking IB Docket No. 96-132 (June 6, 1996).

                  On August 30, 1995, AMSC filed a petition for  reconsideration
         challenging  the  restrictions  placed  by the FCC on the  type of data
         terminal  which  could be  operated  in the  1545-1559/1646.5-1660  MHz
         bands.  That  petition  remains  pending.  On August  31,  1995,  Loral
         Qualcomm   Partnership,    L.P.,   filed   a   petition   for   partial
         reconsideration  requesting  the FCC to declare  that AMSC's  temporary
         authority to operate its data  terminals  in the  1530-1544/1630-1645.5
         MHz bands is secondary to  operation of regularly  licensed  systems in
         these bands and should cease when regularly  licensed  terminals become
         operational in these bands. That petition also is pending.

                  AMSC's blanket voice and data mobile  terminal  authorizations
         are  subject  to  compliance   with  certain   requirements   regarding
         interference  protection to the Global Positioning System (GPS) and the
         Russian Global Navigation  Satellite System (GLONASS).  At present, the
         FCC has found that AMSC's  terminals  comply  with these  requirements.
         However,  these  requirements  are the subject of ongoing review by the
         Radio Technical Commission for Aeronautics (RTCA) Special Committee 159
         (SC-159).  The  FCC  has  made  these  authorizations  subject  to  any
         subsequent   FCC  decision   resulting  from  future  RTCA  reports  or
         recommendations  regarding interference  protection standards to GPS or
         GLONASS,  and may  require  action on the part of AMSC to  conform  its
         terminals to any  modification  of the  Commission's  requirements.  In
         addition, the Commission is currently reviewing its standards for radio
         frequency  radiation  emissions.  ET Docket 93-62.  The  Commission has
         stated that it will require AMSC to demonstrate compliance

                                        2





         with any new standards that the Commission may develop
         as a result of this review.

         (d) Temporary  authorizations  for various mobile terminals.  On August
         23, 1995, the FCC granted AMSC special  temporary  authority to provide
         space  segment  for  the  testing  of  aeronautical   mobile  terminals
         employing AMSC-1 space segment. File No. 1473-SSA-95.  Applications for
         extension of this  authority  have been granted by the FCC. The current
         authority   expires  on  October  18,   1996.   AMSC  may  not  provide
         aeronautical  service  until the FCC  grants  type  acceptance  for the
         terminals  to be used in such a  service.  The FCC  recently  has  type
         accepted certain aeronautical terminals for use with the AMSC system.

                  The FCC granted  AMSC  licenses to  construct  and operate two
11-meter transmit/receive earth stations at Reston, Virginia (Call Sign E930124)
and Alexandria,  Virginia (Call Sign E940374)  (November 4, 1994).  The licenses
provide for the operation of these earth stations on frequency bands  compatible
with AMSC's operation of its mobile terminals in the  1545-1559/1646.5-1660  MHz
bands. On August 11, 1995, the FCC granted AMSC special  temporary  authority to
operate these earth stations on frequency bands compatible with AMSC's temporary
operation  of its  mobile  terminals  in the  1530-1544/1630-1645.5  MHz  bands.
Applications  for extension of this  authority have been granted by the FCC. The
current authority expires on September 27, 1996.

                  AMSC has pending an  application  for  permanent  authority to
operate AMSC-1 in the  1530-1544/1630-1645.5 MHz bands. File No. 59-DSS-MP/ML-93
(July 7, 1993). This application was opposed. The FCC has proposed to grant AMSC
exclusive  authority to operate in these bands to the extent necessary to ensure
that AMSC, after international frequency coordination,  has access to a total of
28 MHz of mobile link  spectrum.  Notice of Proposed  Rulemaking,  IB Docket No.
96-132 (June 6, 1996).  Also, AMSC has pending  applications for modification of
its second and third  satellites to include  additional  frequencies,  File Nos.
15/16-DSS-MP-91,  and for  extension  of the  milestones  for  commencement  and
completion of construction and launch of these satellites.

                                        3





File No. 56/57-DSS-AMEND-94.  AMSC's most recent extension  request was filed on
February 29,  1996,  and  requests  extension  of  the  milestones  for
commencement of construction of these satellites until September, 1996. Earlier
similar requests were opposed.

                  The FCC granted  AMSC special  temporary  authority to repoint
AMSC-1.5 degrees in connection with the  reconfiguration of its spotbeams.  This
authority expires October 12, 1996.

                  The FCC  authorized  AMSC to be the sole domestic  provider of
mobile satellite service in its assigned  frequencies,  with certain exceptions,
based on the FCC's concern that there is not  sufficient  spectrum for more than
one such system.  These exceptions  include:  the use of Inmarsat  satellites to
provide  maritime   services;   the  use  of  Inmarsat   satellites  to  provide
aeronautical  services  on  flights  to and from the  United  States,  including
aeronautical  services  on  domestic  legs  of  international  flights;  and the
provision of interim domestic  aeronautical service by licensees other than AMSC
pending the  availability of operational  domestic  service by AMSC. The FCC has
opened a proceeding  in which it seeks  comment on how it should define or limit
the geographical scope of permissible international  aeronautical services using
the Inmarsat  system in the United  States.  Notice of Proposed  Rulemaking,  CC
Docket  No.  87-75,  FCC  96-161  (April  9,  1996).  Additionally,  the FCC has
undertaken a review of its policies  regarding  general access to U.S.  domestic
markets by non-U.S.  licensed satellite systems.  Notice of Proposed Rulemaking,
IB Docket No. 96-111, FCC 96-210 (May 9, 1996).  Comsat Personal  Communications
Inc. has filed an application for blanket  authority to construct and operate up
to 5,000  Planet 1 mobile  earth  stations in the 1525  MHz-1544  MHz and 1626.5
MHz-1645.5  MHz bands for use  throughout  the national  territory of the United
States in conjunction with Inmarsat satellite.  File No. 1281-DSE-P/L 96 (Public
Notice Report No. DS-1637, June 12, 1996). That application is pending.

                  Pursuant to passage of the Telecommunications Act of 1996, the
Bell  Operating  Companies  are now  permitted  to offer  interexchange  service
(including  Mobile  Satellite  Service) in  connection  with their  provision of
cellular and other mobile services. This removes restrictions that had been

                                        4





interpreted  to  preclude  BOC  cellular   subsidiaries  from  marketing  AMSC's
services. Some question remains, however, as to the legal ability of the BOCs to
offer  AMSC's  service  to fixed  sites.  Such an issue  should  be  within  the
jurisdiction of the FCC to resolve. The  Telecommunications  Act also contains a
provision  prohibiting  carriers from charging  different  rates to customers in
different states.  The FCC has begun a proceeding to consider the implementation
of this provision that may inhibit AMSC's ability to charge different prices for
operating in different beams.

                                        5





                                  ATTACHMENT II



AMSC ALIEN OWNERSHIP


                                                                                                  Attributable
                                                                 Percentage       Alien              Alien
                 Stockholder                Shares Held          Held           Percentage        Percentage
                                                                                          
Hughes                                        6,666,622             26.66%           5.00%             1.33%
Mtel*                                           511,872              2.05%           3.01%             0.06%
Singapore Telecommunications, Ltd.            4,106,546             16.42%         100.00%            16.42%
AT&T**                                        3,001,145             12.00%           7.50%             0.90%
Ronald Baron                                  2,013,933              8.05%           0.00%             0.00%
Other Known Stockholders***                   1,653,785              6.61%           2.79%             0.18%
Other Stockholders                            7,056,785             28.22%           8.90%             2.51%
         TOTAL                               25,010,668            100.00%                            21.41%
*Mtel Interests:
         Mtel Space Technologies
           Corporation                              577              0.00%           3.01%             0.00%
         Mtel Space Technologies, L.P.          397,040              1.59%           3.01%             0.05%
         Mtel Technologies, Inc                 114,255              0.46%           3.01%             0.01%
                  Total Mtel                    511,872              2.05%                             0.06%
**AT&T Interests:
         Satellite Communications
           Investment Company                 1,113,135              4.45%           7.50%             0.33%
         Space Technologies Investments
           Inc.                               1,206,192              4.82%           7.50%             0.36%
         Transit Communications Inc.            681,818              2.73%           7.50%             0.20%
                  Total AT&T                  3,001,145             12.00%                             0.90%
***Other Known Subsidiaries
         Albert L. Zesiger                       40,000              0.16%           0.00%             0.00%
         American Mobile Satellite Profit
           Shr Plan                              10,491              0.04%           0.00%             0.00%
         BOA Personal Trust                      92,000              0.37%           0.00%             0.00%
         Boston Safe                            369,400              1.48%           0.60%             0.01%
         FNB Chicago                             64,255              0.34%           0.00%             0.00%
         Goldman                                108,000              0.43%           0.00%             0.00%
         ML Safekeeping                         196,047              0.78%           3.21%             0.03%
         Morgan Stn                             344,080              1.38%          10.91%             0.15%
         PNC Bank, NA                           280,500              1.12%           0.00%             0.00%
         Witter Reynolds                        128,562              0.51%           0.39%             0.00%
                                              1,653,785              6.61%           2.79%             0.19%



                                        1






              EXHIBIT A - Opinion of Special Counsel for the Agents




                                   OPINION OF
                     DAVIS POLK & WARDWELL, SPECIAL COUNSEL
                                 FOR THE AGENTS




                                                              June 28,  1996


To the Banks and the Agents
  Referred to Below
c/o Morgan Guaranty Trust Company
  of New York, as Documentation Agent
60 Wall Street
New York, New York  10260

Dear Sirs:

                  We have  participated in the  preparation of the  $150,000,000
Credit Agreement (the "Credit  Agreement")  dated as of June 28, 1996 among AMSC
Subsidiary Corporation, a Delaware corporation dually incorporated as a Virginia
Public  Service   Corporation  (the   "Borrower"),   American  Mobile  Satellite
Corporation,  a Delaware corporation (the "Parent Guarantor"),  the banks listed
on the signature  pages thereof (the "Banks"),  Morgan Guaranty Trust Company of
New York,  as  Documentation  Agent  and  Toronto  Dominion  (Texas),  Inc.,  as
Administrative  Agent  (collectively,  the "Agents"),  and have acted as special
counsel for the Agents for the purpose of  rendering  this  opinion  pursuant to
Section 3.1(a) of the Credit  Agreement.  Terms defined in the Credit  Agreement
are used herein as therein defined.

                  We have examined  originals or copies,  certified or otherwise
identified  to  our  satisfaction,   of  such  documents,   corporate   records,
certificates of public  officials and other  instruments and have conducted such
other  investigations  of fact and law as we have deemed  necessary or advisable
for purposes of this opinion.

                                        1





                  Upon the basis of the  foregoing,  we are of the opinion  that
assuming that the  execution,  delivery and  performance  by the Borrower of the
Credit  Agreement  and the  Notes  and by the  Parent  Guarantor  of the  Credit
Agreement  are  within  such  Person's  corporate  powers  and  have  been  duly
authorized by all necessary corporate action, the Credit Agreement constitutes a
valid and binding  agreement of the Borrower and the Parent  Guarantor  and each
Note  constitutes a valid and binding  obligation of the Borrower,  in each case
enforceable in accordance with its terms except as may be limited by bankruptcy,
insolvency or similar laws affecting  creditors' rights generally and by general
principles of equity.

                  We are  members  of the Bar of the  State  of New York and the
foregoing opinion is limited to the laws of the State of New York. In giving the
foregoing opinion, we express no opinion as to the effect (if any) of any law of
any  jurisdiction  (except  the State of New York) in which any Bank is  located
which limits the rate of interest that such Bank may charge or collect.

                  This opinion is rendered  solely to you in connection with the
above  matter.  This opinion may not be relied upon by you for any other purpose
or relied upon by any other person without our prior written consent.

                                                     Very truly yours,

                                        2





                 EXHIBIT B - Assignment and Assumption Agreement



                       ASSIGNMENT AND ASSUMPTION AGREEMENT




                  AGREEMENT dated as of          , 19   among [NAME OF ASSIGNOR]
                                        ---------    --
(the  "Assignor"),   [NAME  OF  ASSIGNEE]  (the  "Assignee"),   AMSC  SUBSIDIARY
CORPORATION   (the   "Borrower")  and  TORONTO   DOMINION   (TEXAS),   INC.,  as
Administrative Agent (the "Agent").

                  WHEREAS,   this  Assignment  and  Assumption   Agreement  (the
"Agreement")  relates to the $150,000,000  Credit Agreement dated as of June 28,
1996  among the  Borrower,  American  Mobile  Satellite  Corporation,  as Parent
Guarantor,  the Assignor  and the other Banks party  thereto,  as Banks,  Morgan
Guaranty Trust Company of New York, as Documentation Agent, and the Agent (the
"Credit Agreement");

                  WHEREAS, as provided under the Credit Agreement,  the Assignor
has a Commitment to make Loans to the Borrower in an aggregate  principal amount
at any time outstanding not to exceed $ ;*
                                       ----------

                  WHEREAS,  Loans made to the Borrower by the Assignor under the
Credit   Agreement  in  the  aggregate   principal  amount  of  $            are
                                                                 ----------
outstanding at the date hereof; and

                  WHEREAS,  the Assignor  proposes to assign to the Assignee all
of the rights of the Assignor under the Credit Agreement in respect of a portion
of its Commitment thereunder in an amount equal to $ (the
                                                                 ----------
"Assigned  Amount"),  together with a  corresponding  portion of its outstanding
Loans, and the Assignee  proposes to accept assignment of such rights and assume
the corresponding obligations from the Assignor on such terms;
- --------
     *To be modified if assignment occurs after Commitments
have terminated.


                                        1





                  NOW,  THEREFORE,  in  consideration  of the  foregoing and the
mutual agreements contained herein, the parties hereto agree as follows:

                  1.  Definitions.  All capitalized terms not
otherwise defined herein shall have the respective meanings
set forth in the Credit Agreement.

                  2.  Assignment.  The Assignor  hereby assigns and sells to the
Assignee  all of the rights of the  Assignor  under the Credit  Agreement to the
extent of the Assigned  Amount,  and the Assignee hereby accepts such assignment
from the Assignor and assumes all of the  obligations  of the Assignor under the
Credit  Agreement to the extent of the Assigned  Amount,  including the purchase
from the Assignor of the  corresponding  portion of the principal  amount of the
Loans made by the Assignor  outstanding  at the date hereof.  Upon the execution
and delivery hereof by the Assignor, the Assignee,  [the Borrower and the Agent]
and the payment of the amounts specified in Section 3 required to be paid on the
date hereof (i) the Assignee shall, as of the date hereof, succeed to the rights
and be obligated to perform the obligations of a Bank under the Credit Agreement
with a  Commitment  in an  amount  equal to the  Assigned  Amount,  and (ii) the
Commitment of the Assignor  shall,  as of the date hereof,  be reduced by a like
amount and the Assignor released from its obligations under the Credit Agreement
to the extent such obligations have been assumed by the Assignee. The assignment
provided for herein shall be without recourse to the Assignor.

                  3.  Payments.  As consideration for the assignment and sale
contemplated in Section 2 hereof, the Assignee shall pay to the Assignor on the
date hereof in Federal funds the amount heretofore agreed between them.3 It is
understood that commitment and/or facility fees accrued to the date hereof are
- --------
     3 Amount  should  combine  principal  together  with  accrued  interest and
breakage compensation, if any, to be paid by the Assignee, net of any portion of
any upfront fee to be paid by the Assignor to the Assignee. It may be preferable
in an appropriate case to specify these amounts generically or by formula rather
than as a fixed sum.

                                        2





for the account of the Assignor and such fees  accruing  from and  including the
date hereof are for the account of the  Assignee.  Each of the  Assignor and the
Assignee hereby agrees that if it receives any amount under the Credit Agreement
which is for the account of the other party  hereto,  it shall  receive the same
for the account of such other party to the extent of such other party's interest
therein and shall promptly pay the same to such other party.

                  [4.  Consent of the Borrower and the Agent.  This Agreement is
conditioned  upon the consent of the Borrower and the Agents pursuant to Section
10.6(c) of the Credit Agreement. The execution of this Agreement by the Borrower
and the Agents is evidence of this  consent.  Pursuant to Section  10.6(c),  the
Borrower  agrees  to  execute  and  deliver a Note  payable  to the order of the
Assignee to evidence the assignment and assumption provided for herein.]

                  5.   Non-Reliance   on  Assignor.   The   Assignor   makes  no
representation  or warranty in connection with, and shall have no responsibility
with  respect  to, the  solvency,  financial  condition,  or  statements  of the
Borrower or the Parent  Guarantor,  or the  validity and  enforceability  of the
obligations  of the  Borrower or the Parent  Guarantor  in respect of the Credit
Agreement or any Note. The Assignee acknowledges that it has,  independently and
without reliance on the Assignor, and based on such documents and information as
it has deemed  appropriate,  made its own credit  analysis and decision to enter
into this  Agreement  and will  continue  to be  responsible  for making its own
independent  appraisal of the business,  affairs and financial  condition of the
Borrower.

                  6.  Governing Law.  This Agreement shall be governed by and
construed in accordance with the laws of the State of New York.

                  7.  Counterparts.  This Agreement may be signed in any number
of counterparts, each of which shall be an original, with the same effect as if
the signatures thereto and hereto were upon the same instrument.


                                        3





                  IN WITNESS WHEREOF,  the parties have caused this Agreement to
be executed and delivered by their duly authorized officers as of the date first
above written.


                               [NAME OF ASSIGNOR]


                                                 By
                                                   -------------------------
                                      Name:
                                     Title:



                               [NAME OF ASSIGNEE]


                                                 By
                                                   -------------------------
                                      Name:
                                     Title:



                                                 AMSC SUBSIDIARY CORPORATION


                                                 By
                                                   -------------------------
                                      Name:
                                     Title:


                                                 TORONTO DOMINION (TEXAS), INC.,
                                                      as Administrative Agent


                                                 By
                                                   ---------------------------
                                      Name:
                                     Title:


                                        4












                                                                     EXHIBIT E-1


                           NOTICE OF NEW SECURED PARTY



Bank of America National Trust
  and Savings Association, as Collateral Agent
Agency Management Services #5596
1455 Market Street, 12th Floor
San Francisco, California 94103
Attention:   Dietmar Schiel
             Vice President


                          Notice re: New Secured Party

Gentlemen:

                  This   notice   is   delivered   pursuant   to  that   certain
Intercreditor and Collateral Agency Agreement (the  "Intercreditor  Agreement"),
dated as of March 15,  1995,  by and among  Bank of America  National  Trust and
Savings  Association  as agent  for the  Syndicate  Bank  (the  "Syndicate  Bank
Agent"),  the Designated  Senior  Lenders from time to time party  thereto,  the
Other  Secured  Lenders  from time to time  party  thereto,  and Bank of America
National Trust and Savings Association as collateral agent ("Collateral  Agent")
for the benefit and on behalf of the Secured  Parties.  Terms not defined herein
have the meanings assigned to them in the Intercreditor Agreement.

                  The   undersigned  and  AMSC   Subsidiary   Corporation   (the
"Company")  hereby represent and warrant that the undersigned has extended or is
extending credit to the Company under a Designated Senior Indebtedness  Facility
or  another  Other  Financing  Facility.  The  undersigned  desires  to become a
"Secured Party" as defined in the Intercreditor Agreement.


                                        1





                  The  undersigned  agrees to be a party to, and be bound by the
terms of, the Intercreditor  Agreement as fully and to the same extent as if the
undersigned were a Designated Senior Lender originally signing the Intercreditor
Agreement.

                  The undersigned  and the Company hereby  represent and warrant
to the Secured Parties that:

                           The indebtedness  owing to the undersigned (i) is not
                  fully  subordinated in Lien priority (if applicable) and right
                  to repayment of the loans under the Syndicate  Bank  Facility,
                  and (ii) has a  weighted  average  life to its final  maturity
                  which is not less than that of the loans  under the  Syndicate
                  Bank Facility.

                           The undersigned is a Designated Senior
                  Lenders Agent.

                  The undersigned  holds or agents  indebtedness and commitments
as  described  on the  attached  certificate,  in the form of  Exhibit  1 to the
Intercreditor Agreement.

                  By signing below, each of the Company and the Collateral Agent
consent to and acknowledge the undersigned becoming a party to the Intercreditor
Agreement.

                  The following administrative details apply to the undersigned:

                  (A)  Notice Address:

                  Morgan Guaranty Trust Company
                    of New York, as Documentation Agent
                  60 Wall Street
                  New York, New York 10260
                  Attention:
                              ------------------
                  Telephone:  (212)
                                   -------------
                  Telecopier: (212)
                                   -------------

                                Very truly yours,

                                                  MORGAN GUARANTY TRUST COMPANY
                                                    OF NEW YORK, as
                                                     Documentation Agent


                                                  By:
                                                      ------------------------
                                                  Title:
                                                         ---------------------

                                        2







ACKNOWLEDGE AND AGREED TO:

AMSC SUBSIDIARY CORPORATION



By:
    ------------------------

Title:
       ---------------------


AMERICAN MOBILE SATELLITE CORPORATION


By:
    -------------------------

Title:
       ----------------------


BANK OF AMERICA NATIONAL TRUST AND
  SAVINGS ASSOCIATION,
as Collateral Agent



By:
   ------------------------------
            Dietmar Schiel
            Vice President

                                        4





                                                                     EXHIBIT E-2



                     NOTICE OF AMOUNT OF SECURED OBLIGATIONS


                                                         Date:    [Closing Date]


Bank of America National Trust
  and Savings Association, as Collateral Agent
Agency Management Services #5596
1455 Market Street, 12th Floor
San Francisco, California 94103
Attention:  Dietmar Schiel
            Vice President


                    Notice re: Amount of Secured Obligations

Gentlemen:

                  This   notice   is   delivered   pursuant   to  that   certain
Intercreditor and Collateral Agency Agreement (the  "Intercreditor  Agreement"),
dated as of March 15,  1995,  by and among  Bank of America  National  Trust and
Savings  Association  as agent for the  Syndicate  Banks  (the  "Syndicate  Bank
Agent"),  the Designated  Senior  Lenders from time to time party  thereto,  the
Other  Secured  Lenders  from time to time  party  thereto,  and Bank of America
National Trust and Savings Association as collateral agent ("Collateral  Agent")
for the benefit and on behalf of the Secured  Parties.  Terms not defined herein
have the meanings assigned to them in the Intercreditor Agreement.

                  The   undersigned  and  AMSC   Subsidiary   Corporation   (the
"Company") hereby represent and warrant that the undersigned is an agent for the
following credit to the Company under a Designated Senior Indebtedness  Facility
or another Other Financing Facility:

         1.       Designated Senior Indebtedness              [        ]
                                                               --------
                  Other Secured Indebtedness                  [        ]
                                                               --------

         2.       Principal amount outstanding:               $

                                        1





         3.       Total additional
                  commitment, if any:                         $

         4.       Nature of Secured Obligation (i.e.
                  term loan, revolving loan, lease, etc.):

         5.       Tenor(s) of principal and commitment:

         6.       Weighted average life:

         7.       Other information:


                                Very truly yours,

                          MORGAN GUARANTY TRUST COMPANY
                       OF NEW YORK, as Documentation Agent



                                           By:
                                               -------------------------
                                           Title:
                                                  ----------------------

ACKNOWLEDGED AND AGREED TO:

AMSC SUBSIDIARY CORPORATION



By:
     -----------------------

Title:
       ---------------------


                                        2





                                                                      EXHIBIT F



                      FORM OF PRINCIPAL SUBSIDIARY GUARANTY


                               CONTINUING GUARANTY


TO:  Toronto Dominion (Texas), Inc.,
          as Administrative Agent


                             PRELIMINARY STATEMENTS:

                  A. AMSC Subsidiary  Corporation,  a Delaware  corporation (the
"Company"), the Banks named therein (the "Banks"), Morgan Guaranty Trust Company
of New York,  as  Documentation  Agent and Toronto  Dominion  (Texas),  Inc., as
Administrative  Agent  (the  "Agent"),  are  parties  to a  $150,000,000  Credit
Agreement  dated as of June 28, 1996 (said  Agreement,  as it may  hereafter  be
amended,  supplemented,  restated or otherwise  modified  from time to time,  is
referred to herein as the "Credit Agreement").

                  B. The  undersigned  Guarantor  ("Guarantor")  is a  Principal
Subsidiary of the Company and it is a requirement  of the Credit  Agreement that
the Guarantor  enter into this Guaranty  guaranteeing  all  obligations of every
nature of the  Company  from time to time owed under or in respect of the Credit
Agreement and other Loan Documents (the "Guarantied Obligations").


                  NOW, THEREFORE, the Guarantor agrees as follows:

                  1.  For  valuable  consideration,  the  undersigned  Guarantor
unconditionally,  absolutely and  irrevocably  guarantees and promises to pay to
the Agent,  or order,  on  demand,  when due  (whether  by  scheduled  maturity,
required prepayment,  acceleration, demand, or otherwise) in lawful money of the
United States and in immediately  available funds, any and all present or future
Guarantied  Obligations  owing to the  Agent and the  Banks  (collectively,  the
"Guarantied Parties"). The term Guarantied Obligations is used herein in its

                                        1





most comprehensive sense and include any and all advances,  debts,  obligations,
and liabilities of the Company,  now, or hereafter made,  incurred,  or created,
whether  voluntary or  involuntarily,  and however arising,  including,  without
limitation,  any and all attorneys' fees, costs, premiums,  charges, or interest
owed by the Company to the Guarantied Parties,  whether due or not due, absolute
or contingent, liquidated or unliquidated,  determined or undetermined,  whether
the Company may be liable individually or jointly with others,  whether recovery
upon such  indebtedness  may be or  hereafter  becomes  barred by any statute of
limitations or whether such  indebtedness  may be or hereafter  become otherwise
unenforceable.

                  2.  Notwithstanding the foregoing,  the liability of Guarantor
under this guaranty shall be limited to an aggregate amount equal to the largest
amount  that would not render its  obligations  hereunder  subject to  avoidance
under  Section  548 of the  United  States  Bankruptcy  Code  or any  comparable
provisions of any applicable state law.

                  3. This Guaranty is a continuing guaranty which relates to any
Guarantied Obligation, including those which arise under successive transactions
which  shall  either  cause the  Company  to incur new  Guarantied  Obligations,
continue the Guarantied  Obligations from time to time, or renew them after they
have been  satisfied.  The  Guarantor  agrees that  nothing  shall  discharge or
satisfy its obligations created hereunder except for the full payment in cash of
the Guarantied Obligations with interest as applicable.

                  4. The  Guarantor  agrees  that it is  directly  liable to the
Agent for the benefit of the  Guarantied  Parties for payment of the  Guarantied
Obligations if the Company has failed to make payment  thereof when due (whether
by scheduled maturity, required prepayment, acceleration, demand, or otherwise),
that its obligations hereunder are independent of the Guarantied  Obligations of
the Company,  or of any other  guarantor,  and that a separate action or actions
may be brought and prosecuted  against the Guarantor,  whether action is brought
against  the  Company or  whether  the  Company is joined in any such  action or
actions. The Guarantor agrees that any releases which may be given by the

                                        2





Guarantied  Parties to the Company or any other  guarantor  shall not release it
from this Guaranty.

                  5. The  obligations of the Guarantor under this Guaranty shall
not be affected,  modified or impaired upon the occurrence  from time to time of
any of the  following,  whether  or not with  notice  to or the  consent  of the
Guarantor:

                  (a)  the compromise, settlement, change, modification,
amendment (whether material or otherwise) or partial termination of any or all
of the Guarantied Obligations;

                  (b)  the failure to give notice to the Guarantor of the
occurrence of any Event of Default under the terms and provisions of the
Agreement;

                  (c)  the waiver of the payment, performance or observance of
any of the Guarantied Obligations;

                  (d) the taking or omitting to take any actions referred to in
the Agreement or of any action under this Guaranty;

                  (e)  any  failure,  omission  or  delay  on  the  part  of the
Guarantied  Parties to enforce,  assert or exercise  any right,  power or remedy
conferred in this Guaranty, the Credit Agreement, any other Loan Document or any
other  indulgence or similar act on the part of the  Guarantied  Parties in good
faith and in compliance with applicable law;

                  (f) the  voluntary or  involuntary  liquidation,  dissolution,
sale or other disposition of all or substantially all of the assets, marshalling
of assets, receivership,  insolvency,  bankruptcy, assignment for the benefit of
creditors or  readjustment  of, or other  similar  proceedings  which affect the
Guarantor,  any other  guarantor  of any of the  Guarantied  Obligations  of the
Company or any of the assets of any of them, or any  allegation of invalidity or
contest of the validity of this Guaranty in any such proceeding;


                                        3





                  (g) to the extent  permitted  by law, the release or discharge
of any other  guarantors of the Guarantied  Obligations  from the performance or
observance of any obligation,  covenant or agreement contained in any guaranties
of the Guarantied Obligations by operation of law; or

                  (h) the  default  or failure  of any other  guarantors  of the
Guarantied  Obligations fully to perform any of their respective obligations set
forth in any such guaranties of the Guarantied Obligations.

         To the  extent any of the  foregoing  refers to any  actions  which the
Guarantied  Parties may take,  the Guarantor  hereby agrees that the  Guarantied
Parties may take such actions in such manner, upon such terms, and at such times
as the Guarantied Parties, in their discretion, deem advisable,  without, in any
way or respect, impairing,  affecting,  reducing or releasing the Guarantor from
its undertakings  hereunder and the Guarantor hereby consents to each and all of
the foregoing actions, events and occurrences.

                  6.  The Guarantor hereby waives:

                  (a) any and all rights to require  the  Guarantied  Parties to
prosecute or seek to enforce any remedies against the Company or any other party
liable to the Guarantied Parties on account of the Guarantied Obligations;

                  (b) any right to assert  against  the  Guarantied  Parties any
legal or  equitable  defense  (other  than  indefeasible  payment in full of the
Guarantied  Obligations  or as expressly  provided in this  Guaranty),  set-off,
counterclaim, or claim which the Guarantor may now or at any time hereafter have
against the Company or any other party liable to the  Guarantied  Parties in any
way or manner under the Credit Agreement;

                  (c) all  defenses,  counterclaims  and off-sets of any kind or
nature,  arising  directly  or  indirectly  from the  present or future  lack of
perfection, sufficiency, validity or enforceability of any Loan Document and the
security interest granted pursuant thereto;

                                        4





                  (d) any  defense  arising  by reason  of any claim or  defense
based upon an election of remedies by the Guarantied Parties including,  without
limitation,  any direction to proceed by judicial or nonjudicial  foreclosure or
by deed  in lieu  thereof,  which,  in any  manner  impairs,  affects,  reduces,
releases, destroys or extinguishes the Guarantor's subrogation rights, rights to
proceed  against  the  Company  for  reimbursement,  or any other  rights of the
Guarantor  to proceed  against  the  Company,  against any other  guarantor,  or
against any other security,  with the Guarantor  understanding that the exercise
by the Guarantied Parties of certain rights and remedies may offset or eliminate
the Guarantor's right of subrogation against the Company, and that the Guarantor
may therefore incur partially or totally non- reimbursable  liability hereunder;
and

                  (e) all  presentments,  demands  for  performance,  notices of
non-performance,  protests,  notices of protest, notices of dishonor, notices of
default,  notice of acceptance of this  Guaranty,  and notices of the existence,
creation, or incurring of new or additional indebtedness,  and all other notices
or formalities to which the Guarantor may be entitled.

                  7. The  Guarantor  hereby  agrees  that  unless  and until all
Guarantied  Obligations  have been paid to the  Guarantied  Parties in full,  it
shall not have any  rights of  subrogation,  reimbursement  or  contribution  as
against the Company or any other guarantor, if any, and shall not seek to assert
or  enforce  the  same.  The  Guarantor  understands  that the  exercise  by the
Guarantied  Parties  of  certain  rights  and  remedies  contained  in the  Loan
Documents may affect or eliminate the  Guarantor's  right of subrogation if any,
against the Company and that the Guarantor  may  therefore  incur a partially or
totally non-reimbursable liability hereunder; nevertheless, the Guarantor hereby
authorizes  and  empowers  the  Guarantied  Parties to  exercise,  in their sole
discretion,  any right and remedy, or any combination thereof, which may then be
available,  since  it is the  intent  and  purpose  of the  Guarantor  that  the
obligations hereunder shall be absolute, independent and unconditional under any
and all circumstances.


                                        5





                  8.  The  Guarantor  is  presently  informed  of the  financial
condition of the Company and of all other circumstances which a diligent inquiry
would  reveal  and which  bear  upon the risk of  nonpayment  of the  Guarantied
Obligations. The Guarantor hereby covenants that it will continue to keep itself
informed  of the  financial  condition  of the  Company,  the  status  of  other
guarantors,  if any, and of all other  circumstances which bear upon the risk of
nonpayment.  The  Guarantor  hereby  waives its right,  if any,  to require  the
Guarantied  Parties  to  disclose  to it any  information  which they may now or
hereafter acquire concerning such condition or circumstances  including, but not
limited to, the release of any other guarantor.

                  9. The Guarantied  Parties'  books and records  evidencing the
Guarantied Obligations shall be admissible in any action or proceeding and shall
be binding  upon the  Guarantor  for the purpose of  establishing  the terms set
forth therein and shall constitute prima facie proof thereof.

                  10.  The Guarantor represents and warrants for and with
respect to itself that:

                  (a) The Guarantor is a corporation duly organized and existing
under the laws of the state of , and is properly  licensed and in good  standing
in, and where necessary to maintain its rights and privileges have complied with
the  fictitious  name  statute  of,  every  jurisdiction  in  which  it is doing
business,  except  where the failure to be  licensed  or be in good  standing or
comply  with any such  statute  will not have a material  adverse  effect on the
ability of the  Guarantor  to perform  its  obligations  hereunder  or under any
instrument or agreement required hereunder;

                  (b) The execution,  delivery and  performance of this Guaranty
and any instrument or agreement  required  hereunder are within the power of the
Guarantor,  have been duly authorized by, and are not in conflict with the terms
of any charter, by-law or other organization papers of, the Guarantor;


                                        6





                  (c) No  approval,  consent,  exemption  or other action by, or
notice to or filing with, any governmental  authority is necessary in connection
with the execution, delivery, performance or enforcement of this Guaranty or any
instrument or agreement required hereunder, except as may have been obtained and
certified  copies of which  have  been  delivered  to Agent  and the  Guarantied
Parties;

                  (d)  There is no law,  rule or  regulation,  nor is there  any
judgment,  decree or order of any court or governmental authority binding on the
Guarantor, which would be contravened by the execution, delivery, performance or
enforcement of this Guaranty or any instrument or agreement required hereunder;

                  (e) This Guaranty is a legal,  valid and binding  agreement of
the Guarantor,  enforceable  against the Guarantor in accordance with its terms,
and any instrument or agreement required hereunder, when executed and delivered,
will  be  similarly  legal,  valid,   binding  and  enforceable,   except  where
enforceability  thereof may be limited by applicable law relating to bankruptcy,
insolvency,  moratorium  or  other  similar  laws  affecting  creditors'  rights
generally or by the application of general principles of equity;

                  (f) There is no action, suit or proceeding pending against, or
to  the  knowledge  of  the  Guarantor,  threatened  against  or  affecting  the
Guarantor,  before any court or arbitrator or any governmental  body,  agency or
official which in any manner draws into question that validity or enforceability
of this Guaranty; and

                  (g) The execution,  delivery and  performance by the Guarantor
of this Guaranty does not constitute,  to the best knowledge of the Guarantor, a
"fraudulent conveyance," "fraudulent obligation" or "fraudulent transfer" within
the meanings of the Uniform  Fraudulent  Conveyances  Act or Uniform  Fraudulent
Transfer Act, as enacted in any jurisdiction.

                  11.  Any one of the following events shall constitute a
"Guarantor Event of Default:"


                                                    7





                  (a) The Guarantor is generally not paying or admits in writing
its  inability  to pay its debts as such debts become due, or files any petition
or action  for  relief  under any  bankruptcy,  reorganization,  insolvency,  or
moratorium law or any other law for the relief of, or relating to, debtors,  now
or hereafter in effect, or makes any assignment for the benefit of creditors, or
takes any corporate action in furtherance of any of the foregoing;

                  (b) An  involuntary  petition is filed  against the  Guarantor
under any  bankruptcy  statute  now or  hereafter  in  effect,  or a  custodian,
receiver,  trustee,  assignee  for the benefit of  creditors  (or other  similar
official) is appointed to take possession, custody or control of any property of
the Guarantor,  unless such petition or appointment is set aside or withdrawn or
ceases to be in effect  within  sixty (60) days from the date of said  filing or
appointment.

                  THEN, any and all of the  Guarantor's  obligations  under this
Guaranty shall become due, payable and enforceable against the Guarantor whether
or not the Guarantied  Obligations are then due and payable without presentment,
demand,  protest  or other  requirements  of any kind,  all of which are  hereby
expressly  waived by the Guarantor,  and the obligation of each Bank to make any
Loan under the Credit Agreement shall thereupon terminate.

                  12. This  Guaranty  shall be binding upon the  successors  and
assigns  of the  Guarantor  and shall  inure to the  benefit  of the  Guarantied
Parties'  successors  and  assigns.  This  Guaranty  cannot be  assigned  by the
Guarantor  without the prior written  consents of the  Guarantied  Parties which
shall be in the Guarantied Parties' sole and absolute discretion.

                  13.  No  failure  or  delay  by  the  Guarantied   Parties  in
exercising  any right,  power or privilege  hereunder  shall operate as a waiver
thereof nor shall any single or partial  exercise  thereof preclude any other or
further exercise thereof or the exercise of any other right, power or privilege.
The rights and remedies herein provided shall be cumulative and not exclusive of
any rights or remedies provided by law.

                                        8





                  14.  The  Guarantor  shall  pay  all  out-of-pocket   expenses
incurred  by  the  Agent  and  the  Guarantied   Parties,   including  fees  and
disbursements  of counsel  (including the allocated cost of inhouse  counsel and
staff), in connection with the enforcement of this Guaranty (whether or not suit
is brought).

                  15. No  modification  of this Guaranty  shall be effective for
any purpose  unless it is in writing and executed by an officer of the Agent and
the  Guarantor  authorized  to do so.  This  Guaranty  merges all  negotiations,
stipulations  and  provisions  relating to the subject  matter of this  Guaranty
which preceded or may accompany the execution of this Guaranty.

                  16.  This  Guaranty  and the  rights  and  obligations  of the
parties  hereunder  shall be construed in accordance with and be governed by the
laws of the State of New York without  reference to the  principles of conflicts
of laws thereof.

                  17.   This   Guaranty   may  be  executed  in  any  number  of
counterparts and by the different parties hereto on separate counterparts,  each
of which when so executed and delivered  shall be an original,  but all of which
shall together constitute one and the same instrument.

                  18. Any  indebtedness  of the Company now or hereafter held by
the Guarantor is hereby  subordinated to the  indebtedness of the Company to the
Agent and the Guarantied  Parties;  and such  indebtedness of the Company to the
Guarantor if the Agent so requests shall be collected,  enforced and received by
the  Guarantor as trustee for the Agent and the  Guarantied  Parties and be paid
over to the Agent on account of the indebtedness of the Company to the Agent and
the  Guarantied  Parties but without  reducing  or  affecting  in any manner the
liability of the Guarantor under the other provisions of this Guaranty.

                  19. The effectiveness of this Guaranty is subject to condition
that the Agent shall have received all of the  following,  in form and substance
satisfactory to the Agent and the Banks and in sufficient copies for each Bank:


                                        9





                  (a) Resolutions; Incumbency Certificate.

                           (i)  Copies  of  the  resolutions  of  the  board  of
         directors of the Guarantor  approving and  authorizing  the  execution,
         delivery and  performance of this Guaranty by the Guarantor,  certified
         as of the date hereof by the Secretary or an Assistant Secretary of the
         Guarantor; and

                           (ii) A  certificate  of the  Secretary  or  Assistant
         Secretary of the Guarantor  certifying the names and true signatures of
         the officers of the  Guarantor  authorized  to execute and deliver this
         Guaranty.

                  (b) Articles of Incorporation; By-laws and Good
Standing of the Guarantor. Each of the following documents:

                           (i) the articles or certificate of  incorporation  of
         the  Guarantor  as in  effect  on the  date  hereof,  certified  by the
         Secretary of State of the State of incorporation of the Guarantor as of
         a recent  date  and by the  Secretary  or  Assistant  Secretary  of the
         Guarantor  as of the date hereof and the bylaws of the  Guarantor as in
         effect on the date  hereof,  certified  by the  Secretary  or Assistant
         Secretary of the Guarantor as of the date hereof; and

                           (ii) a good  standing  certificate  for the Guarantor
         from the  Secretary  of State of its  state of  incorporation  and each
         state  where the  Guarantor  is  qualified  to do business as a foreign
         corporation as of a recent date.

                  20. Unless otherwise  specified  herein or therein,  all terms
defined in this  Guaranty  shall have  meanings  assigned  to them in the Credit
Agreement.

                  21. All notices and other  communications  hereunder  shall be
delivered,  in the manner and with the effect  provided in the Credit  Agreement
and, in the case of the Guarantor, care of the Company.

                  22. It is not necessary for the Guarantied Parties to inquire
into the powers of any Guaranteed Party or of the officers, directors or agents
acting or purporting to act on its behalf,  and any indebtedness made or

                                        1




created  in  reliance  upon  the  professed  exercise  of such  powers  shall be
guaranteed hereunder.


                  Executed as of the      day of         ,      .


                                   [Guarantor]


                                             By:
                                             Title:


                                             TORONTO DOMINION (TEXAS), INC.,
                             as Administrative Agent


                                             By:



                                        1