SECOND AMENDMENT
                                TO REVOLVING NOTE

      THIS SECOND AMENDMENT TO REVOLVING NOTE ("Second Amendment"), made as of
November 14, 2000, by and among United Industrial Corporation, a Delaware
corporation, having an address of 570 Lexington Avenue, New York, New York
10022, and AAI Corporation, AAI Engineering Support, Inc., AAI/ACL Technologies,
Inc., AAI/ACL Technologies Europe Limited, Detroit Stoker Company, Midwest
Metallurgical Laboratory, Inc., UIC Products Co., and AAI MICROFLITE Simulation
International Corporation (collectively, the "Borrower"), and First Union
Commercial Corporation, a North Carolina Corporation (the "Lender").

                                    RECITALS

      A.    United Industrial Corporation and certain of its subsidiaries
            entered into a Revolving Note, dated as of June 11, 1997, in the
            maximum principal amount of Seventeen Million, Five Hundred Thousand
            Dollars ($17,500,000.00) made payable to the order of First Union
            Commercial Corporation, as amended by First Amendment to Revolving
            Note, dated March 31, 2000 (the "Revolving Note").

      B.    The Revolving Note evidences Borrower's obligations to repay
            advances of principal made by the Lender under a Revolving Line of
            Credit Loan Agreement And Security Agreement, dated June 11, 1997,
            as amended by First Amendment to Revolving Line of Credit Loan
            Agreement and Security Agreement dated as of October 1, 1998, by
            Second Amendment to Revolving Line of Credit Loan Agreement and
            Security Agreement dated as of December 31, 1998, by Third Amendment
            to Revolving Line of Credit Loan Agreement, Term Loan Agreement and
            Security Agreement, made as of March 31, 2000, by Fourth Amendment
            to Revolving Line of Credit Loan Agreement and Security Agreement,
            dated as of September 21, 2000, and by Fifth Amendment to Revolving
            Line of Credit Loan Agreement and Security Agreement, of even date
            herewith (the "Loan Agreement"). The Revolving Note is governed, in
            part, by certain provisions of the Loan Agreement.

      C.    The Borrower and the Lender desire to amend the Revolving Note for
            the purpose of extending the Maturity Date (as defined in the
            Revolving Note) to June 30, 2001, for the purpose of changing the
            definition of "Borrower" to the definition set forth above and for
            certain other purposes hereinafter set forth.

                                   AGREEMENTS

      NOW, THEREFORE, in consideration of the premises, the mutual agreements
herein contained, and other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the Borrower and the Lender hereby
agree as follows:


1.    Capitalized terms used in this First Amendment but not defined herein have
      the meanings ascribed to them in the Revolving Note. The term "Borrower"
      shall henceforth refer to the Persons encompassed by the term "Borrower"
      as defined above.

2.    The Maturity Date is extended to and including June 30, 2001.

3.    Except as modified by this Second Amendment, the Revolving Note remains in
      full force and effect and unmodified. Borrower warrants and represents
      that it has no offsets or defenses to its obligations under the Revolving
      Note, as modified by this Second Amendment.

4.    In consideration of Lender's agreement to this Second Amendment, the
      Borrower hereby releases and waives any and all claims of any kind that it
      may have against the Lender as of the date of this First Amendment arising
      out of or relating to the Loan Agreement or the Revolving Note, as amended
      by this Second Amendment.

5.    ARBITRATION. UPON DEMAND OF ANY PARTY HERETO, WHETHER MADE BEFORE OR AFTER
      INSTITUTION OF ANY JUDICIAL PROCEEDING, ANY CONTROVERSY OR CLAIM ARISING
      OUT OF OR RELATING TO THE LOAN DOCUMENTS BETWEEN PARTIES HERETO (A
      "DISPUTE") SHALL BE RESOLVED BY BINDING ARBITRATION CONDUCTED UNDER AND
      GOVERNED BY THE COMMERCIAL FINANCIAL DISPUTES ARBITRATION RULES (THE
      "ARBITRATION RULES") OF THE AMERICAN ARBITRATION ASSOCIATION ("AAA") AND
      THE FEDERAL ARBITRATION ACT. DISPUTES MAY INCLUDE, WITHOUT LIMITATION,
      TORT CLAIMS, COUNTERCLAIMS, A DISPUTE AS TO WHETHER A MATTER IS SUBJECT TO
      ARBITRATION, CLAIMS BROUGHT AS CLASS ACTIONS, OR CLAIMS ARISING FROM
      DOCUMENTS EXECUTED IN THE FUTURE. A JUDGMENT UPON THE AWARD MAY BE ENTERED
      IN ANY COURT HAVING JURISDICTION. NOTWITHSTANDING THE FOREGOING, THIS
      ARBITRATION PROVISION DOES NOT APPLY TO DISPUTES UNDER OR RELATED TO SWAP
      AGREEMENTS. ALL ARBITRATION HEARINGS SHALL BE CONDUCTED IN THE CITY OR
      COUNTY WHERE THE LENDER'S OFFICE, AS FIRST STATED ABOVE, IS LOCATED, OR AT
      SUCH OTHER PLACE AS THE PARTIES MAY IN WRITING AGREE. A HEARING SHALL
      BEGIN WITHIN 90 DAYS OF DEMAND FOR ARBITRATION AND ALL HEARINGS SHALL
      CONCLUDE WITHIN 120 DAYS OF DEMAND FOR ARBITRATION. THESE TIME LIMITS MAY
      NOT BE EXTENDED UNLESS A PARTY SHOWS CAUSE FOR EXTENSION AND THEN FOR NO
      MORE THAN A TOTAL OF 60 DAYS. THE EXPEDITED PROCEDURES SET FORTH IN RULE
      51, ET SEQ., OF THE ARBITRATION RULES SHALL APPLY TO DISPUTES ------- IN
      WHICH THE CLAIM IS LESS THAN $1,000,000.00. ARBITRATORS SHALL BE LICENSED
      ATTORNEYS SELECTED FROM THE COMMERCIAL FINANCIAL DISPUTE ARBITRATION PANEL
      OF THE AAA. THE PARTIES DO NOT WAIVE


                                       2


      APPLICABLE FEDERAL OR STATE SUBSTANTIVE LAW EXCEPT AS PROVIDED HEREIN.
      NOTWITHSTANDING THE PRECEDING BINDING ARBITRATION PROVISIONS, THE PARTIES
      AGREE TO PRESERVE WITHOUT DIMINUTION, CERTAIN REMEDIES THAT ANY PARTY MAY
      EXERCISE BEFORE OR AFTER AN ARBITRATION PROCEEDING IS BROUGHT. THE PARTIES
      SHALL HAVE THE RIGHT TO PROCEED IN ANY COURT OF PROPER JURISDICTION OR BY
      SELF HELP TO EXERCISE OR PROSECUTE THE FOLLOWING REMEDIES, AS APPLICABLE:
      (1) ALL RIGHTS TO FORECLOSE AGAINST ANY REAL OR PERSONAL PROPERTY OR OTHER
      SECURITY BY EXERCISING A POWER OF SALE OR UNDER APPLICABLE LAW BY JUDICIAL
      FORECLOSURE INCLUDING A PROCEEDING TO CONFIRM THE SALE; (2) ALL RIGHTS OF
      SELF HELP, INCLUDING WITHOUT LIMITATION, PEACEFUL OCCUPATION OF REAL
      PROPERTY AND COLLECTION OF RENTS, SETOFF, AND PEACEFUL POSSESSION OF
      PERSONAL PROPERTY; (3) OBTAINING PROVISIONAL OR ANCILLARY REMEDIES
      INCLUDING INJUNCTIVE RELIEF, SEQUESTRATION, GARNISHMENT, ATTACHMENT,
      APPOINTMENT OF RECEIVER AND FILING AN INVOLUNTARY BANKRUPTCY PROCEEDING;
      AND (4) WHEN APPLICABLE, A JUDGMENT BY CONFESSION OF JUDGMENT. ANY CLAIM
      OR CONTROVERSY WITH REGARD TO ANY PARTY'S ENTITLEMENT TO SUCH REMEDIES IS
      A DISPUTE. THE PARTIES AGREE THAT THEY SHALL NOT HAVE A REMEDY OF PUNITIVE
      OR EXEMPLARY DAMAGES AGAINST OTHER PARTIES IN ANY DISPUTE, AND THEY HEREBY
      WAIVE ANY RIGHT OR CLAIM TO PUNITIVE OR EXEMPLARY DAMAGES THEY MAY NOW
      HAVE OR WHICH MAY ARISE IN THE FUTURE IN CONNECTION WITH ANY DISPUTE
      WHETHER THE DISPUTE IS RESOLVED BY ARBITRATION OR JUDICIALLY.

6.    Lender has executed this Second Amendment for the sole purpose of
      evidencing its consent hereto, and not for the purpose of becoming liable
      on the Revolving Note as a co- maker, endorser or guarantor.

7.    This Second Amendment may be signed in several counterparts which, when
      executed, shall constitute a single agreement. A counterpart containing a
      facsimile signature shall be effective to the same extent as if it were a
      counterpart containing an original signature, but shall be confirmed
      promptly with a counterpart containing an original signature.


BORROWER:                           UNITED INDUSTRIAL CORPORATION


                                    By  /s/ James Perry
                                       --------------------------------
                                          James Perry, Vice President


                                       3


                                    AAI CORPORATION


                                    By: /s/ James Perry
                                       --------------------------------
                                          James Perry, Vice President


                                    AAI ENGINEERING SUPPORT, INC.


                                    By: /s/ Richard Erkeneff
                                       --------------------------------
                                          Richard Erkeneff, President


                                    AAI/ACL TECHNOLOGIES, INC.


                                    By: /s/ Thomas E. Wurzel
                                       --------------------------------
                                          Thomas E. Wurzel, President


                                    AAI/ACL TECHNOLOGIES EUROPE LIMITED


                                    By: /s/ Thomas E. Wurzel
                                       --------------------------------
                                          Thomas E. Wurzel, President


                                    DETROIT STOKER COMPANY


                                    By: /s/ James Perry
                                       --------------------------------
                                          James Perry, Vice President


                                    MIDWEST METALLURGICAL LABORATORY,
                                    INC.


                                    By: /s/ James Perry
                                       --------------------------------
                                          James Perry, Vice President


                                       4


                                    UIC PRODUCTS CO.


                                    By: /s/ James Perry
                                       --------------------------------
                                          James Perry, Vice President


                                    AAI MICROFLITE Simulation International
                                    Corporation


                                    By: Stanley J. Mecinski, Jr.
                                       --------------------------------
                                          Stanley J. Mecinski, Jr.
                                          Assistant Secretary and Assistant
                                          Treasurer


CONSENTED TO:                       FIRST UNION COMMERCIAL CORPORATION


                                    By: /s/ Scott Santa Cruz
                                       --------------------------------
                                          Scott Santa Cruz, Vice President


STATE OF MARYLAND        )
COUNTY/CITY OF BALTIMORE ) To Wit:

      I Nancy K. Yates-Miller, a Notary Public in and for the jurisdiction
aforesaid, do certify that James Perry, whose name is signed to the writing
above, bearing date as of November 13, 2000, has acknowledged the same before me
in my jurisdiction aforesaid.

      Given under my hand and seal this 13th day of November, 2000.

                                          /s/ Nancy K. Yates-Miller
                                          -------------------------
                                          Notary Public

My Commission Expires: October 31, 2001


                                       5


STATE OF MARYLAND        )
COUNTY/CITY OF BALTIMORE ) To Wit:

      I Nancy K. Yates-Miller, a Notary Public in and for the jurisdiction
aforesaid, do certify that Richard Erkeneff, whose name is signed to the writing
above, bearing date as of November 13, 2000 has acknowledged the same before me
in my jurisdiction aforesaid.

      Given under my hand and seal this 13th day of November, 2000.

                                          /s/ Nancy K. Yates-Miller
                                          -------------------------
                                          Notary Public

My Commission Expires: October 31, 2001


STATE OF MARYLAND        )
COUNTY/CITY OF BALTIMORE ) To Wit.

      I Nancy K. Yates-Miller, a Notary Public in and for the jurisdiction
aforesaid, do certify that Thomas E. Wurzel, President, whose name is signed to
the writing above, bearing date as of November 13, 2000, has acknowledged the
same before me in my jurisdiction aforesaid.

      Given under my hand and seal this 13th day of November, 2000.

                                          /s/ Nancy K. Yates-Miller
                                          -------------------------
                                          Notary Public

My Commission Expires: October 31, 2001


STATE OF MARYLAND        )
COUNTY/CITY OF BALTIMORE ) To Wit

      I Nancy K. Yates-Miller, a Notary Public in and for the jurisdiction
aforesaid, do certify that Stanley J. Mecinski, Jr., whose name is signed to the
writing above, bearing date as of November 13, 2000 has acknowledged the same
before me in my jurisdiction aforesaid.

      Given under my hand and seal this 13th day of November, 2000.

                                          /s/ Nancy K. Yates-Miller
                                          -------------------------
                                          Notary Public

My Commission Expires: October 31, 2001


                                      6