FOURTH AMENDMENT TO CREDIT AGREEMENT


                  This  Amendment is made as of the ____ day of August,  1996 by
and between FIELDS AIRCRAFT SPARES INCORPORATED,  a California  corporation (the
"Borrower"),  and NORWEST  BUSINESS CREDIT,  INC., a Minnesota  corporation (the
"Lender").

                                    RECITALS

                  The  Borrower  and the Lender have entered into the Credit and
Security  Agreement  dated as of  February  9,  1995 and  amended  by the  First
Amendment to Credit  Agreement dated November 21, 1995, the Second  Amendment to
Credit  Agreement  dated February 29, 1996 and the Third Amendment to the Credit
Agreement dated June 30, 1996, (as amended, the "Credit Agreement").

                  The Borrower may request certain advances from the Lender from
time to time  pursuant  to the  Credit  Agreement,  and the Lender  may,  in its
discretion,  choose  to  make  loans  to the  Borrower  pursuant  to the  Credit
Agreement.  The Lender may demand repayment of the loans at any time pursuant to
the terms of the Credit Agreement.

                  The loan advances under the Credit  Agreement are evidenced by
the  Borrower's  demand  promissory  note dated as of February  9, 1995,  in the
maximum principal amount of Ten Million Dollars ($10,000,000) and payable to the
order of the Lender (the "Note").

                  All  indebtedness  of the  Borrower  to the  Lender is secured
pursuant to the terms of the Credit  Agreement and all other Security  Documents
as defined therein  (collectively,  the "Security  Documents") and is guaranteed
pursuant to the  unconditional  guaranties of the Corporate  Guarantors  defined
therein and is further  guaranteed  pursuant to the validity  guaranties  of the
Individual  Validity  Guarantors  defined  therein  (the  "Validity  Guarantors"
collectively with the Corporate Guarantors the "Guarantors")

                  The Borrower has requested that certain  amendments be made to
the Credit Agreement,  which the Lender is willing to make pursuant to the terms
and conditions set forth herein.

                  NOW,  THEREFORE,  in  consideration of the premises and of the
mutual covenants and agreements herein contained, it is agreed as follows:



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         1.       Definitions and Amendments.

                  (a) Terms used in this Fourth  Amendment  which are defined in
         the Credit  Agreement shall have the same meanings as defined  therein,
         unless otherwise defined herein.

                  (b)      The definition of the term "Borrowing Base" is hereby
         amended as follows:  "Borrowing Base" means, at any time and subject to
         change from time to time in the Lender's sole discretion, the lesser of

                           (i) $6,900,000 provided,  however, that the Borrowing
                  Base shall be decreased by Two Hundred Fifty Thousand  Dollars
                  ($250,000) on the 1st day of October, 1996 and on the same day
                  of each successive month thereafter.

                  or

                           (ii)     the sum of

                           (iii) the lesser of (A) 75% of  Eligible  Accounts or
                  (B) $6,900,000; provided, however, that such maximum amount of
                  Eligible  Accounts  shall be reduced by  $250,000 on the first
                  day of  October,  1996 and on the same day of each  successive
                  month thereafter, plus

                           (iv) the lesser of (A) 50% of Eligible  Inventory  or
                  (B) $6,500,000; provided, however, that such maximum amount of
                  Eligible  Inventory  shall be reduced by $100,000 on the first
                  day of  October,  1996 and on the same day of each  successive
                  month thereafter, plus

                           (v)      $250,000

                  (c) The  definition  of the term  "Floating  Rate"  is  hereby
         amended  to mean an annual  rate equal to the sum of the Base Rate plus
         five and one-half percent (5.5%), which Floating Rate shall change when
         and as the Base Rate changes;  provided, however that the Floating Rate
         shall be  increased  by  one-half  percent  (0.5%)  on the first day of
         October, 1996 and on the same day of each successive month thereafter.

                  (d)      Paragraph (d) and (e) of Section 2.12 Fees, is hereby
         amended as follows:

                           (i) The  Borrower  agrees to pay to Lender  annually,
                  commencing  with the fiscal year ending  December 31, 1995 and
                  for each fiscal year (or portion  thereof)  thereafter  during
                  the term of this  Agreement,  a fee  equal to 2% of the  Gross
                  Profit  in  excess  of  $2,000,000  as shown on the  financial
                  statements  delivered  pursuant to Section  6.1  hereof,  with
                  respect to each such fiscal year, privided that such fee shall

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                  in no  event be greater than $150,000  or less  than  $50,000.
                  Such fee  shall be  payable annually  upon the earliest of (i)
                  the  delivery  of  the  audited  financial  statements for the
                  fiscal year with respect to which such fee is paid as required
                  pursuant to Section 6.1 hereof,  (ii) the  termination of this
                  Agreement,  or (iii) demand for repayment of the Advances. The
                  fee payable upon termination or demand  shall be equal  to the
                  sum  of  any  unpaid  fee for the fiscal  year ended  prior to
                  such termination regardless of  whether the audited  financial
                  statements have been delivered with respect to such year, plus
                  the fee for the portion of the  fiscal  year  ended  as of the
                  end  of  the  month  immediately  proceeding the  date of such
                  termination of demand. The fee for  such  partial  year  shall
                  be  equal to 2% of the Gross  Profit  therefor  in  excess  of
                  $2,000,000,  as  shown  on the  interim  financial  statements
                  delivered  pursuant  to  Section  6.1  hereof  for  the  month
                  immediately  preceding  the  date  of  termination or  demand,
                  provided  that such fee shall in no event be  greater     than
                  $150,000   or  less  than   $4,166.67   times  the  number  of
                  months  of such  partial  fiscal  year  prior  to the  date of
                  termination or demand.

                  (e) Commencing  July 25, 1996,  the Borrower  hereby agrees to
         pay the Lender monthly in advance an accommodation fee of $7,500.  This
         accommodation  fee will be  increased  to $15,000  per month  beginning
         October 25, 1996.

         1.       Fee.    Borrower agrees to pay a fee of Fifty-Thousand Dollars
($50,000) for this Amendment.

         2.       No  Other  Amendments.  Except  as  explicitly amended by this
Amendment,  all of the terms and conditions of the Credit Agreement shall remain
in full force and effect and shall apply to any advance thereunder.

         3.       Conditions.  This  Fourth  Amendment  shall  be effective (the
"Effective  Date") upon  receipt by the Lender of an executed  original  hereof,
together with each of the  following,  each in substance and form  acceptable to
the Lender in its sole discretion:

                  (a) The  Acknowledgement and Agreement of Guarantors set forth
         at the end of this  Amendment,  duly executed by each of the Guarantors
         and the Acknowledgment and Agreement of Validity Guarantors.

                  (b) Supplemental  Secretary's  Certificate  certifying (i) the
         resolutions  of the board of directors of the  Borrower  approving  the
         execution  and  delivery  of this  Amendment,  (ii) the  fact  that the
         Articles of  Incorporation  and the Bylaws of the Borrower,  which were
         certified and delivered to the Lender  pursuant to the  Certificate  of
         the  Borrower's  Secretary  dated as of February 9, 1995 in  connection
         with the  execution  and delivery of the Credit  Agreement  continue in
         full force and effect  and have not been  amended or otherwise modified


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         except  as set  forth in the  Certificate  to  bedelivered,  and  (iii)
         certifying  that the  officers and agents of the Borrower who have been
         certified to the Lender,  pursuant to the Certificate of the Borrower's
         Secretary dated as of February 9, 1995, as being authorized to sign and
         to act on  behalf  of the  Borrower  continue  to be so  authorized  or
         setting forth the sample  signatures of each of the officers and agents
         of the Borrower  authorized to execute and deliver this Third Amendment
         and all other  documents,  agreements and certificates on behalf of the
         Borrower.

                  (c)      Such  other  documents  as  the  Lender  in  its sole
         discretion may require.

         4.       Representations and Warranties.

                  (a) The  Borrower  has all  requisite  power and  authority to
         execute  this Fourth  Amendment  and to perform all of its  obligations
         hereunder,  and this  Amendment has been duly executed and delivered by
         the Borrower and constitutes the legal, valid and binding obligation of
         the Borrower, enforceable in accordance with its terms.

                  (b) The execution, delivery and performance by the Borrower of
         this  Amendment  have been duly  authorized by all necessary  corporate
         action and does not (i) require any authorization,  consent or approval
         by any governmental  department,  commission,  board, bureau, agency or
         instrumentality, domestic or foreign, (ii) violate any provision of any
         law,  rule or regulation  or of any order,  writ,  injunction or decree
         presently  in effect,  having  applicability  to the  Borrower,  or the
         articles of incorporation  or by-Laws of the Borrower,  or (iii) result
         in a breach of or  constitute a default  under any indenture or loan or
         credit agreement or any other  agreement,  lease or instrument to which
         the Borrower is a party or by which it or its  properties  may be bound
         or affected.

                  (c) All of the  representations  and  warranties  contained in
         Article V of the  Credit  Agreement  are  correct on and as of the date
         hereof as though made on and as of such date, except to the extent that
         such representations and warranties relate solely to an earlier date.

         5.  References.  Upon the Effective  Date, all references in the Credit
Agreement to "this  Agreement"  shall be deemed to refer to the Credit Agreement
as amended hereby;  and any and all references in the Security  Documents to the
Credit  Agreement  shall be deemed to refer to the Credit  Agreement  as amended
hereby.

         6. No Waiver.  The Borrower  acknowledges that it failed to demonstrate
minimum Net  Earnings as required by Section  6.13 of the Credit  Agreement  and
that this failure constitutes an Event of Default under the Credit Agreement. In
addition to any other rights under the Credit agreement,  the Lender is entitled
to have the  outstanding  principal of the Advances bear interest at the Default
Rate. As of the  date hereof,  the Lender  in its  discretion has not elected to

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exercise  such right.  The  execution of the Fourth  Amendment and any documents
related  hereto shall not be deemed to be a waiver of (i) such events of Default
or any other Event of Default under the Credit  Agreement or breach,  default or
event of default  under any  Security  Document  or other  document  held by the
Lender,  whether or not known to the Lender and  whether or not  existing on the
date of this Fourth  Amendment or (ii) any of Lender's rights and remedies under
the Loan Documents, including without limitation its rights under Section 2.3 of
the Credit  Agreement to have the  outstanding  principal  of the Advances  bear
interest at the Default Rate.

         7. Release. The Borrower hereby absolutely and unconditionally releases
and  forever  discharges  the  Lender,  and  any and  all  participants,  parent
corporations,   subsidiary  corporations,   affiliated  corporations,  insurers,
indemnitors,  successors and assigns  thereof,  together with all of the present
and former  directors,  officers,  agents and employees of any of the foregoing,
from any and all  claims,  demands  or causes  of action of any kind,  nature or
description,  whether arising in law or equity or upon contract or tort or under
any state or federal law or  otherwise,  which the  Borrower has had, now has or
has made  claim to have  against  any such  person  for or by reason of any act,
omission,  matter,  cause or thing whatsoever arising from the beginning of time
to and including the date of this  Amendment,  whether such claims,  demands and
causes of action are matured or unmatured or known or unknown.

         8.  Expenses.  The Borrower  hereby  reaffirms its agreement  under the
Credit  Agreement  to pay or  reimburse  the  Lender on demand for all costs and
expenses  incurred by the Lender in connection  with the Credit  Agreement,  the
Security  Documents  and all other  documents  contemplated  thereby,  including
without  limitation  all  reasonable  fees and  disbursements  of legal counsel.
Without  limiting the  generality of the  foregoing,  the Borrower  specifically
agrees  to pay all fees and  disbursements  of  counsel  to the  Lender  for the
services  performed by such counsel in connection  with the  preparation of this
Fourth  Amendment and the  documents  and  instruments  incidental  hereto.  The
Borrower  hereby agrees that the Lender may, at any time or from time to time in
its sole discretion and without further  authorization  by the Borrower,  make a
loan to the Borrower  under the Credit  Agreement,  or apply the proceeds of any
loan,  for the  purpose  of  paying  any such  fees,  disbursements,  costs  and
expenses.

         9.  Counterparts.  This Fourth  Amendment and the  Acknowledgement  and
Agreement  of  Corporate  Guarantors  and the  Acknowledgment  and  Agreement of
Validity Guarantors may be executed in any number of counterparts, each of which
when so executed  and  delivered  shall be deemed an  original  and all of which
counterparts, taken together, shall constitute one and the same instrument.


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                  IN WITNESS WHEREOF, the parties hereto have caused this Fourth
Amendment to be duly executed as of the day and year first above written.

                   BORROWER:

                   FIELDS AIRCRAFT SPARES INCORPORATED (SEAL)


                   By:______________________________________
                   Its:_____________________________________


                   LENDER:

                   NORWEST BUSINESS CREDIT, INC. (SEAL)


                   By:_____________________________________
                   Its:____________________________________


              ACKNOWLEDGMENT AND AGREEMENT OF CORPORATE GUARANTORS

         The  undersigned,  a guarantor of the  indebtedness  of FIELDS AIRCRAFT
SPARES  INCORPORATED  (the  "Borrower") to NORWEST  BUSINESS  CREDIT,  INC. (the
"Lender") pursuant to Corporate Guaranty dated as of February 9, 1996 hereby (i)
acknowledge receipt of the foregoing Fourth Amendment.






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