KEEP WELL AGREEMENT


                  This KEEP WELL  AGREEMENT  is dated as of April 1,  1997,  and
made by TRITON AVIATION SERVICES LIMITED,  a Bermuda  corporation  ("TASL"),  in
favor of TRITON  AVIATION  SERVICES  III LLC,  a  California  limited  liability
company (the  "Borrower"),  and in favor of POLARIS  AIRCRAFT INCOME FUND III, a
California limited partnership (the "Lender") (the "Agreement").

                                R E C I T A L S:

                  WHEREAS,  the Lender has entered  into a Purchase,  Assignment
and  Assumption  Agreement  dated as of April 1,  1997 with the  Borrower  (said
Agreement,  as it may  hereafter be amended or otherwise  modified  from time to
time,  being  the  "Purchase  Agreement",  the  terms  defined  therein  and not
otherwise  defined  herein  being  used  herein  as  therein  defined)  and,  in
connection therewith, the Borrower has delivered to the Lender a promissory note
effective as of April 1, 1997 in the amount of $9,713,711 (the "Note"); and

                  WHEREAS,  TASL, as the owner of 99 percent of the  outstanding
member interests in the Borrower,  will derive  substantial  direct and indirect
economic  benefit from the transactions  contemplated by the Purchase  Agreement
and the delivery of the Note to the Lender; and

                  WHEREAS,  in connection with the execution and delivery of the
Purchase  Agreement and the Note,  the Lender is requiring  that TASL shall have
executed and delivered this Agreement;

                  NOW, THEREFORE,  in consideration of the premises and in order
to induce the Lender to enter into the Purchase Agreement and accept delivery of
the Note, TASL hereby agrees as follows:


SECTION 1.  Obligation  to Cause the Borrower to Perform.  (a) TASL shall pay to
the  Borrower  from  time to time,  in cash in  United  States  dollars  through
additional  contributions to the equity of the Borrower,  amounts  sufficient to
permit the Borrower  promptly to perform all of its obligations  under the Note,
the Security Agreement and the Purchase Agreement.



















                  (b) Notwithstanding anything to the contrary contained herein,
TASL shall not be required to make  unrecouped  payments under this Agreement to
the Borrower or the Lender in excess of an aggregate of $956,111  (the  "Maximum
Obligation") at any time outstanding;  provided,  however, that any dividends or
other  distributions made by the Borrower (other than dividends or distributions
made in respect of any Equity  Dividend  Amount,  as such term is defined in the
Note),  shall be deemed to be made in  recoupment  of any payments  made by TASL
hereunder and the aggregate  amount of TASL's  obligation  under  subsection (a)
above shall be restored by the amount of such  dividend or  distribution,  up to
the Maximum Obligation.

                  (c) If TASL  shall at any time and from  time to time  fail to
perform or comply with any of its obligations  contained in subsection (a) above
and if for any  reason  the Lender  shall  have  failed to receive  when due and
payable (whether at stated maturity, by acceleration,  or otherwise) the payment
of all or any part of the  principal  of or  interest  on the Note or any  other
amount payable by the Borrower thereunder or under the Security Agreement or the
Purchase Agreement, then in each such case:

                       (i) it shall be conclusively assumed without necessity of
         proof that such  failure  by TASL was the sole and direct  cause of the
         Lender  failing to receive such payment  when due  irrespective  of any
         other contributing or intervening cause whatsoever;

                       (ii) TASL agrees that it will be  unconditionally  liable
         to the Lender for liquidated  damages (for loss of a bargain and not as
         a penalty)  for the amount of such  payment not  received by the Lender
         when so due and payable as well as for all costs and expenses,  if any,
         incurred by the Lender in  enforcing  this  Agreement  (but only to the
         extent of and as a reduction of the Maximum Obligation);

                       (iii) TASL further  irrevocably waives to the full extent
         permitted by applicable law any right or defense TASL may have to cause
         the Lender to prove the cause or amount of such  damages or to mitigate
         the same; and

                       (iv) since TASL has agreed to  liquidated  damages in the
         amount specified above, the Lender shall not be entitled to any damages
         in excess of such amount with respect to such payment.

                  (d)  Notwithstanding  anything herein to the contrary,  during
any period in which the Lender shall have failed to receive when due and payable




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(whether at stated maturity, by acceleration or otherwise) the payment of all or
any part of the principal of or interest on the Note or any other amount payable
by the  Borrower  thereunder  or under the  Security  Agreement  or the Purchase
Agreement, TASL shall make payment of all funds under this Agreement directly to
the Lender c/o Polaris Investment  Management  Corporation,  201 Mission Street,
27th Floor,  San Francisco,  CA 94105,  and the Lender shall apply such funds in
the same manner as though paid directly by the Borrower.  All payments which are
received by the Borrower contrary to the provisions of this subsection (d) shall
be received in trust for the benefit of the  Lender,  shall be  segregated  from
other funds and  property  held by the  Borrower,  and shall be paid over to the
Lender in the same form as so received (with any necessary indorsement).

                  SECTION 2. Other Permitted Payments. If and to the extent that
amounts paid to the Borrower  pursuant to Section 1(a) do not exceed the Maximum
Obligation,  TASL may make  payments to the  Borrower  from time to time for any
purpose in which the  Borrower  is  permitted  to  engage,  and in each case the
amount of such  payment  shall be credited  against  TASL's  obligation  to make
payments to the Borrower under Section 1(a) hereof up to the Maximum Obligation;
provided,  however, that if the Borrower sells, transfers,  conveys or otherwise
disposes  of an Asset (as such term is defined  in the Note) for an amount  (the
"Sale Price") that is less than 90% of the product of (x) the Allocable  Portion
Percentage  (as defined in the Note) for such Asset  multiplied  by (y) the then
outstanding  balance of the Note,  then any payment made by TASL to the Borrower
in the 60 day  period  preceding  or the  60 day  period  following  such  sale,
transfer,  conveyance or other  disposition  shall be included in determining if
the Maximum  Obligation has been reached only after  deducting (a) the Shortfall
Amount (as defined  below) and (b) any dividends or other  distributions  (other
than dividends or  distributions  in respect of any Equity Dividend Amount) made
by the  Borrower  during both such  periods.  For  purposes  of this  Section 2,
"Shortfall  Amount"  means the amount  that is the  difference  between  (i) the
product of the Allocable  Portion  Percentage for the Asset which has been sold,
transferred,   conveyed  or  otherwise   disposed  of  multiplied  by  the  then
outstanding balance of the Note and (ii) the Sale Price.

                  SECTION 3. Taxes,  Authorizations,  Etc. (a) TASL will pay any
stamp or other tax (including  any interest and  penalties)  with respect to the
performance by TASL of its  obligations  pursuant to this  Agreement;  provided,
however, in no event shall such taxes include any taxes imposed upon or measured
by the gross or net income of the  Borrower  or the  Lender.  If any such tax is
paid by the Lender in the good faith  belief that such tax is owing,  TASL will,
upon demand of the Lender, indemnify the Lender for such payment,  together with




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any  interest,  penalties  and expenses in  connection  therewith  plus interest
thereon  at the lesser of 10% or the  maximum  rate under  applicable  law.  The
Lender shall thereafter cooperate in a commercially  reasonable manner with TASL
in seeking any refunds of such taxes,  interest,  penalties  and expenses  which
refunds and any interest thereon shall be paid by the Lender to TASL within five
(5) business days of receipt by the Lender, provided, that in no event shall the
Lender be  required  to expend  its own funds in  seeking  any such  refund  and
provided,  further,  that any expenses incurred in connection therewith shall be
paid by TASL.

                  (b) TASL will  obtain  any  authorization,  approval  or other
action by, and will give any notice to or make any filing with, any governmental
authority or regulatory body required in connection with the performance by TASL
of its obligations pursuant to this Agreement.

                  SECTION  4.  Obligation   Absolute.   TASL  will  perform  its
obligations under this Agreement  regardless of any law, regulation or order now
or hereafter  in effect in any  jurisdiction  affecting  any of the terms of the
Note,  the Security  Agreement or the Purchase  Agreement or any other  document
related  thereto  or  the  rights  of  the  Lender  with  respect  thereto.  The
obligations  of TASL under this  Agreement  shall be absolute and  unconditional
irrespective of:

                       (i) any lack of validity,  enforceability or value of the
         Purchase  Agreement,  the Note,  the  Security  Agreement  or any other
         agreement or instrument relating thereto or any collateral therefor;

                       (ii) any  change in any term of the Note  (including  any
         change in the time, manner or place of payment  thereof),  the Security
         Agreement or the Purchase  Agreement,  or any other amendment or waiver
         of or any consent to departure from the Note, the Security Agreement or
         the Purchase Agreement;

                       (iii) any  exchange,  release  or  non-perfection  of any
         collateral,  or any  release  or  amendment  or waiver of or consent to
         departure from any guaranty,  for the Note,  the Security  Agreement or
         the Purchase Agreement;

                       (iv) any  failure  to pay any taxes  which may be payable
         with respect to the  performance  of such  obligations  by TASL, or any
         failure to obtain any  authorization  or approval  from or other action
         by,  or to notify or file  with,  any  Government  Entity  required  in
         connection with the performance of such obligations by TASL; or



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                       (v) any  impossibility or  impracticality of performance,
         illegality,  force majeure,  any act of any Government  Entity,  or any
         other  circumstance which might constitute a defense available to, or a
         discharge  of, TASL or a surety,  or any other  circumstance,  event or
         happening  whatsoever,  whether  foreseen  or  unforeseen  and  whether
         similar or dissimilar to anything referred to above in this Section 4.

This Agreement shall continue to be effective or be reinstated,  as the case may
be, if at any time any payment is rescinded or must otherwise be returned by the
Lender upon the  insolvency,  bankruptcy  or  reorganization  of the Borrower or
otherwise, all as though such payment had not been made. The obligations of TASL
under this  Agreement  shall not be subject to reduction,  termination  or other
impairment by reason of any set-off, recoupment,  counterclaim or defense or for
any other reason.

                  SECTION 5. Waiver.  TASL hereby waives promptness,  diligence,
notice  of  acceptance  and  any  other  notice  with  respect  to the  Purchase
Agreement,  the Note and this  Agreement  and any  requirement  that the  Lender
protect, secure, perfect or insure any security interest or lien or any property
subject  thereto or exhaust any right or take any action against the Borrower or
any other person or entity or any collateral.

                  SECTION  6.  Separate   Undertaking.   Without   limiting  the
generality  of  any  of  the  foregoing  provisions  of  this  Agreement,   TASL
irrevocably  waives,  to the full extent permitted by applicable law and for the
benefit of, and as a separate  undertaking with, the Lender,  any defense to the
performance of this Agreement which may be available to TASL as a consequence of
this  Agreement  being  rejected or otherwise not assumed by the Borrower or any
trustee or other similar  official for the Borrower or for any substantial  part
of the property of the Borrower,  or as a consequence  of this  Agreement  being
otherwise  terminated or modified,  in any proceeding  seeking to adjudicate the
Borrower  a  bankrupt  or   insolvent  or  seeking   liquidation,   winding  up,
reorganization,  arrangement,  protection, relief or composition of the Borrower
or the debts of the Borrower under any law relating to bankruptcy, insolvency or
reorganization  or relief or  protection  of debtors,  whether  such  rejection,
non-assumption, termination or modification be by reason of this Agreement being
held to be an executory contract or by reason of any other circumstance. If this
Agreement  shall be so rejected or otherwise  not assumed,  or so  terminated or
modified,  TASL agrees for the benefit of, and as a separate  undertaking  with,
the  Lender,  that it will be  unconditionally  liable  to pay to the  Lender an
amount equal to each payment  which would  otherwise be payable by TASL under or
in  connection  with this  Agreement if this  Agreement  were not so rejected or
otherwise not assumed or were  otherwise  not so  terminated  or modified,  such




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amount to be payable to the Lender,  as and when such payment would otherwise be
payable  hereunder and such amount to be applied as such payment would otherwise
be applied under the Note.

                  SECTION  7.   Representations  and  Warranties.   TASL  hereby
represents and warrants to Borrower and Lender as follows:

                  (a) TASL (i) is a corporation duly organized, validly existing
         and in good  standing  under  the  laws of  Bermuda  and  (ii)  has the
         requisite  power and  authority  to carry on its  business as presently
         conducted  and as  proposed  to be  conducted  after  the  date of this
         Agreement  and to enter into and  perform  its  obligations  under this
         Agreement.

                  (b)  TASL is the  beneficial  and  record  owner of 99% of all
         outstanding  member  interests  of the  Borrower  free and clear of any
         lien,  security interest or other charge or encumbrance other than that
         set forth in the Security Agreement.

                  (c) The execution and delivery by TASL of this Agreement,  and
         the performance by TASL of its obligations hereunder (i) have been duly
         authorized  by all  necessary  action on the part of TASL,  (ii) do not
         contravene  any  provision  of  law,  governmental  rule,   regulation,
         judgment  or  order   applicable   to  or  binding  on  TASL,   or  the
         organizational  documents  of TASL and (iii) do not require the consent
         or approval of, the giving of notice to, the registration  with, or the
         taking of any other action in respect of, any federal, state or foreign
         governmental  authority  or agency or any other  Person,  except  those
         already obtained.

                  (d) This Agreement has been duly executed and delivered and is
         enforceable  against TASL in accordance with its terms,  subject to the
         effect  of  bankruptcy,   insolvency,   reorganization,   receivership,
         moratorium  and other similar laws affecting the rights and remedies of
         creditors  generally  and, with respect to the  enforceability  of this
         Agreement,  by general  principles of equity,  including  principles of
         commercial  reasonableness,  good faith and fair dealing (regardless of
         whether enforcement is sought in a proceeding at law or in equity).

                  SECTION 8. No Transfer of Interest.  TASL covenants and agrees
that,  so long as the Note  shall  remain  unpaid,  TASL will not sell,  assign,
pledge,  encumber or  otherwise  dispose of any member  interest of the Borrower
except to the extent and in the manner  permitted by the Security  Agreement and
that any  transfer  by it of any  interest  in the  Borrower  shall not  reduce,
release or lessen its obligations under this Agreement.



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                  SECTION 9.  Amendments,  Etc.  No  amendment  or waiver of any
provision of this Agreement nor consent to any departure by TASL therefrom shall
in any event be effective  unless the same shall be in writing and signed by the
Borrower and the Lender, and then such waiver or consent shall be effective only
in the specific instance and for the specific purpose for which given.

                  SECTION  10.  Expenses.  TASL  will  upon  demand  pay  to the
Borrower  and the  Lender,  respectively,  the amount of any and all  reasonable
expenses,  including  attorneys'  fees and expenses,  which the Borrower and the
Lender,  as the case  may be,  may  incur in  connection  with the  exercise  or
enforcement of any of their respective rights or interests hereunder;  provided,
however,  that  TASL  shall  not be  obligated  to pay  any  costs  or  expenses
(including attorney's fees) incurred by the Borrower or the Lender in connection
with the preparation of this Agreement or (x) any ordinary  administrative costs
and  expenses of the  Borrower so long as there is no default by TASL under this
Agreement or (y) any ordinary administrative costs and expenses of the Lender so
long as there is no default by TASL  under  this  Agreement  or a default by the
Borrower  under  the  Purchase  Agreement,  the  Note  or  any  other  Ancillary
Agreement.

                  SECTION 11.  Addresses  for  Notices.  All  notices,  demands,
declarations  and other  communications  required by this Agreement  shall be in
writing and shall be effective (i) if given by facsimile, when transmitted, (ii)
if given by  registered  or  certified  mail,  three  business  days after being
deposited  with the U.S.  Postal  Service,  (iii)  if  given  by  courier,  when
received, or (iv) if personally delivered, when so delivered, addressed:




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                  If to TASL, to:

                         Triton Aviation Services Limited
                         55 Green Street, Suite 500
                         San Francisco, CA  94111
                         Attention:  President
                         Facsimile:  (415) 398-9184

or to such other  address as TASL may from time to time  designate in writing to
the Borrower and Lender.

                  If to the Borrower, to:

                         Triton Aviation Services III LLC
                         55 Green Street, Suite 500
                         San Francisco, CA  94111
                         Attention:  President
                         Facsimile:  (415) 398-9184

or to such other  address as the  Borrower  may from time to time  designate  in
writing to TASL and Lender.

                  If to Lender, to:

                         Polaris Aircraft Income Fund III
                         c/o Polaris Investment Management Corporation
                         201 Mission Street, 27th Floor
                         San Francisco, CA  94105
                         Attention:  President
                         Facsimile:  (415) 284-7460

                  With a copy to:

                         Polaris Aircraft Income Fund III
                         c/o Polaris Investment Management Corporation
                         201 High Ridge Road, 1st Floor
                         Stamford, CT  06927-4900
                         Attention:  Portfolio Management
                         Facsimile:  (203) 357-4585


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or to such other address as Lender shall from time to time  designate in writing
to the Borrower and TASL.

                  SECTION 12. No Waiver; Remedies. No failure on the part of the
Borrower  or the  Lender  to  exercise,  and no delay in  exercising,  any right
hereunder  shall  operate as a waiver  thereof;  nor shall any single or partial
exercise of any right hereunder  preclude any other or further  exercise thereof
or the exercise of any other right.  The remedies herein provided are cumulative
and not exclusive of any remedies provided by law.

                  SECTION  13.  Continuing  Agreement;  Transfer  of Note.  This
Agreement  is a  continuing  agreement  and shall (i)  remain in full  force and
effect until  payment in full and  discharge  of the Note,  (ii) be binding upon
TASL,  its  successors  and  assigns,  and (iii)  inure to the benefit of and be
enforceable  by the  Borrower,  the  Lender  and  their  respective  successors,
transferees and assigns. Without limiting the generality of the foregoing clause
(iii),  the Lender may assign or  otherwise  transfer the Note held by it to any
other person or entity,  and such other person or entity shall thereupon  become
vested with all the rights in respect  thereof  granted to the Lender  herein or
otherwise.

                  SECTION 14.  Governing Law. This  Agreement  shall be governed
by, and construed in accordance with, the laws of the State of California.




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                  IN WITNESS WHEREOF,  TASL has caused this Agreement to be duly
executed and delivered by its officer  thereunto duly  authorized as of the date
first above written.

                                               TRITON AVIATION SERVICES
                                               LIMITED



                                               By: /S/JOHN E. FLYNN
                                                   ---------------------
                                                   Name: JOHN E. FLYNN
                                                   Title: PRESIDENT

The  foregoing  Agreement
is hereby  accepted and 
agreed to as of the date 
first above written:


TRITON AVIATION SERVICES III LLC

By:   Triton Aviation Services
      Limited, Manager


      By:/S/JOHN E. FLYNN
         ---------------------
         Name: JOHN E. FLYNN
         Title: PRESIDENT

POLARIS AIRCRAFT INCOME FUND III

By:   Polaris Investment Management
      Corporation, General Partner


      By:/S/MARC A. MEICHES
         ----------------------
         Name: MARC A. MEICHES
         Title: VICE PRESIDENT




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