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                                                                   Exhibit 10.13


NATIONSBANK, N.A.




                       AMENDED AND RESTATED LOAN AGREEMENT

This Loan Agreement (the "Agreement") dated as of April 30, 1999, by and between
NationsBank, N.A. (the "Bank") and the Borrower described below:

                                    RECITALS
A.    The Borrower and the Bank entered into a Loan Agreement (the Original
      Agreement) dated April 30, 1995.

B.    The Borrower and the Bank entered into a First Amendment to Loan Agreement
      ("First Amendment") dated April 30, 1996 to extend the maturity,, and
      modify certain covenants.

C.    The Borrower and the Bank entered into a Second Amendment to Loan
      Agreement ("First Amendment") dated April 30, 1997 to extend the maturity,
      and modify, certain covenants.

D.    The Borrower and the Bank now wish to further amend the Original Agreement
      to modify certain covenants, increase the amount of the credit facility
      and for certain other matters, as set forth in this Agreement.

      In consideration of the Loan or Loans described below and the mutual
      covenants and agreements contained herein, and intending to be legally,
      bound hereby, Bank and Borrower agree as follows:

      1. DEFINITIONS AND REFERENCE TERMS. In addition to any other terms defined
herein, the following terms shall have the meaning set forth with respect
thereto:

             A.   BORROWER.  Performance Engineering Corporation

             B.   BORROWER'S ADDRESS: 3949 Pender Drive
                                      Suite 300 Fairfax,
                                      Virginia 22030

             C. HAZARDOUS MATERIALS. Hazardous Materials include all materials
defined as hazardous wastes or substances under any local, state or federal
environmental laws, rules or regulations. and petroleum, petroleum products, oil
and asbestos.

             D. LOAN(S). Loan(s) means collectively any and all loans heretofore
or hereafter made by Bank to the Borrower.

             E. LOAN DOCUMENTS. Loan Documents means this Agreement and any and
all promissory notes executed by Borrower in favor of Bank and all other
documents, instruments, guarantees, certificates and agreements executed and/or
delivered by Borrower, any guarantor or third party in connection with any Loan.


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             F. NET INCOME. Net profit after tax excluding all gains on the sale
of assets, and any other extraordinary gains.

             G. TANGIBLE NET WORTH. Tangible Net Worth means the amount by which
total assets exceed total liabilities in accordance with GAAP, less accounts
receivable from affiliates, any surplus resulting from any write up of assets;
goodwill, patents, trademarks, services marks. trade names and copyrights; other
intangible assets, leasehold improvements; investments in non-marketable
securities or affiliated companies, capitalized development costs; and
capitalized expenses.

             H. ACCOUNTING TERMS. All accounting terms not specifically defined
or specified herein hall have the meanings generally attributed to such terms
under generally accepted accounting principles ("GAAP"), as in effect from time
to time, consistently applied, with respect to the financial statements
referenced in Section 3.H. hereof.

      2. LOANS.

         A. LOAN. Bank hereby agrees to make (or has made) a loan or loans to
Borrower in the aggregate principal amount of $2,700,000.00. The obligation to
repay the loan is evidenced by a promissory note or notes dated April 30, 1999
(the promissory, note or notes together with any other promissory notes
heretofore or hereafter executed by Borrower in favor of Bank and any and all
renewals, extensions or rearrangements thereof being hereafter collectively
referred to as the "Note") having a maturity date, repayment terms and interest
rate as set forth in the Note.

         B. REVOLVING CREDIT FEATURE. The Loan provides for a revolving line of
credit (the "Line") under which Borrower may from time to time, borrow, repay
and re-borrow funds.

         C. LETTER OF CREDIT SUBFEATURE. As a subfeature under the Line, the
Bank may from time to time up to and including April 30, 2001. issue letters of
credit for the account of Borrower (each, a "Letter of Credit" and collectively,
"Letters of Credit"); provided, however that the form and substance of each
Letter of Credit shall be subject to approval by Bank in its sole discretion;
and provided further that the aggregate undrawn amount of all outstanding
Letters of Credit shall not at any time exceed $1,400,000.00. Each Letter of
Credit shall be issued for a term not to exceed 365 days, provided that no
Letter of Credit shall have an expiration date subsequent to April 30, 2001,
unless the Letter of Credit is secured by Borrower's cash. The undrawn amount of
all Letters of Credit plus any and all amounts paid by Bank in connection with
drawings under any Letter of Credit for which the Bank has not been reimbursed
shall be reserved under the Line and shall not be available for advances
thereunder. Each draft paid by Bank under a Letter of Credit shall be deemed an
advance under the Line and shall be repaid 'In accordance with the terms of the
Line; provided however that if the Line is not available for any reason
whatsoever, at the time any draft is paid by the Bank, or if advances are not
available under the Line in any such amount due to any limitation of borrowing
set forth herein, then the full amount of such drafts shall be immediately due
and payable, together with interest thereon, from the date such amount is paid
by Bank to the date such amount is fully repaid by Borrower, at that rate of
interest applicable to advances under the Line. In such event, Borrower agrees
that Bank, at Bank's sole discretion may debit Borrower's deposit account with
Bank for the amount of such draft. For each Letter of Credit issued on behalf of
the Borrower under this subfeature, the Borrower shall pay a fee of 1.5% of the
face amount of the Letter of Credit per annum, with a minimum fee of $300.00.
Letters of Credit shall automatically renew for a period of one year upon
maturity unless otherwise specified in advance, with a renewal fee of 1.0%
payable upon renewal, unless the Borrower gives notice 60 days prior to
maturity, of their intent to let the Letter of Credit expire, or if the maturity
of the Loan is less than one year hence.

         D. ADVANCES. Whenever the Borrower desires that the Bank make an
advance under the Line, the Borrower shall provide a notice to the Bank setting
forth (a) the date, which shall be a Business Day, on which such advance shall
be made and (b) the total principal amount of the advance (the "Standard
Notice"). If Standard Notice is provided, no later than 10:00 a.m., Eastern
Standard Time, on the date specified in such Standard Notice, the Bank will make
available the requested funds by depositing such proceeds in the Borrower's
account No. 7922-5641 maintained at the Bank's office. All advances must be in
minimum amounts of $25,000.00.


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         E. INTEREST RATE. The interest rate will float at the option of the
Borrower at the Bank's Prime lending rate, varying as that rate varies from time
to time or the London Inter-Bank Offered Rate plus 250 basis points. Interest
shall be charged and calculated on a 360 day year factor applied to actual days,
and shall be payable monthly. The "PRIME" rate is a reference used by the Bank
in determining interest rates on certain loans and is not intended to be the
lowest rate of interest charged on any extension of credit to any customer.

         F. COMMITMENT FEE. Borrower wi11 pay hereafter on July, 31, 1999 and
continuing on the last day of each successive quarter for the periods from and
including the date the Line was established to and including the maturity date
of the Line, a $5,000.00 fee per annum, payable in quarterly payments of
$1,250.00 per quarter.

      3. REPRESENTATIONS AND WARRANTIES. Borrower hereby represents and warrants
to Bank as follows:

         A. GOOD STANDING. Borrower is a corporation, duly organized, validly
existing and in good standing under the laws of Virginia and has the power and
authority to own its property and to carry on its business in each jurisdiction
in which Borrower does business.

         B. AUTHORITY AND COMPLIANCE. Borrower has full power and authority, to
execute and deliver the Loan Documents and to incur and perform the obligations
provided for therein, all of which have been duly authorized by all proper and
necessary action of the appropriate governing body of Borrower. No consent or
approval of any public authority or other third party is required as a condition
to the validity of any Loan Document, and Borrower is in compliance with all
laws and regulatory requirements to which it is subject.

         C. BINDING AGREEMENT. This Agreement and the other Loan Documents
executed by Borrower constitute valid and legallv binding obligations of
Borrower, enforceable in accordance with their terms.

         D. LITIGATION. There is no proceeding involving Borrower pending or, to
the knowledge of Borrower, threatened before any court or governmental
authority, agency or arbitration authority, except as disclosed to Bank in
writing and acknowledged by Bank prior to the date of this Agreement.

         E. NO CONFLICTING AGREEMENTS. There is no charter, bylaw, stock
provision, partnership agreement or other document pertaining to the
organization. power or authority of Borrower and no provision of any existing
agreement, mortgage, indenture or contract binding on Borrower or affecting its
property, which would conflict with or in any way prevent the execution,
delivery or carrying out of the terms of this Agreement and the other Loan
Documents. F. OWNERSHIP OF ASSETS. Borrower has good title to its assets, and
its assets are free and clear of Liens, except those granted to Bank and as
disclosed to Bank in writing prior to the date of this Agreement.

         G. TAXES. All taxes and assessments due and payable by Borrower have
been p 'd or are being contested in good faith by appropriate proceedings and
the Borrower has filed all tax returns -which it is required to file.

         H. FINANCIAL STATEMENTS. The financial statements of Borrower
heretofore delivered to Bank have been prepared in accordance with GAAP applied
on a consistent basis throughout the period involved and fairly present
Borrower's financial condition as of the date or dates thereof, and there has
been no material adverse change in Borrower's financial condition or operations
since December 31, 1998. To the best of Borrower's knowledge, all factual
information furnished by Borrower to Bank in connection with this Agreement and
the other Loan Documents is and will be accurate and complete on the date as of
which such information is delivered to Bank and is not and will not be
incomplete by the omission of any material fact necessary to make such
information not misleading.


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         I. PLACE OF BUSINESS. Borrower's chief executive office is located at

                           3949 Pender Drive
                           Suite 300
                           Fairfax.  VA 22030

         J. ENVIRONMENTAL MATTERS. ENVIRONMENTAL LAW COMPLIANCE. The conduct of
Borrower's business operations do not and not violate any federal laws, rules or
ordinances for environmental protection, regulations of the Environmental
Protection Agency and any applicable local or state law, rule, regulation or
rule of common law and any judicial interpretation thereof relating primarily to
the environment or Hazardous Materials and Borrower will not use or permit any
other party to use any Hazardous Materials at any of Borrower's places of
business or at any other property owned by Borrower except such materials as are
incidental to Borrower's normal course of business, maintenance and repairs and
which are handled in compliance with all applicable environmental laws. Borrower
agrees to permit Bank, its agents, contractors and employees to enter and
inspect any of Borrower's places of business or any other property of Borrower
at any reasonable times upon three (3) days prior notice for the purposes of
conducting an environmental investigation and audit (including taking physical
samples) to insure that Borrower is complying with this covenant and Borrower
shall reimburse Bank on demand for the costs of any such environmental
investigation and audit. Borrower shall provide Bank, its agents, contractors,
employees and representatives with access to and copies of any and all data and
documents relating to or dealing with any Hazardous Materials used, generated,
manufactured, stored or disposed of by Borrower's business operations within
FIVE (5) days of the request therefore.

         K. YEAR 2000 COMPLIANCE. The Borrower has (1) initiated a review and
assessment of all area within its and each of its subsidiaries' business and
operations (including those affected by suppliers and vendors) that could be
adversely affected by the "Year 2000 Problem" (that is, the risk that computer
applications used by the Borrower or any of its' subsidiaries (or its suppliers
and vendors) may be unable to recognize or perform properlv date-sensitive
functions involving certain dates prior to and any date after December 3 1,
1999), (ii) developed a plan and timetable for addressing the Year 2000 Problem
on a timely basis, and (iii) to date, implemented that plan in accordance ,with
that timetable. The Borrower reasonably believes that all computer applications
(including those of suppliers and vendors) that are material to its or any of
its subsidiaries' business and operations will on a timely basis be able to
perform properly date sensitive functions for all dates before and after January
1. 2000, except to the extent that a failure to do so could not reasonably be
expected to have material adverse effect.

         L. CONTINUATION. OF REPRESENTATION AND WARRANTIES. All representations
and warranties made under this Agreement shall be deemed to be made at and as of
the date hereof and at and as of the date of any future advance under any Loan.

      4. AFFIRMATIVE COVENANTS. Until full payment and performance of all
obligations of Borrower under the Loan Documents, Borrower will, unless Bank
consents otherwise in writing (and without limiting any requirement of any other
Loan Document):

         A. FINANCIAL CONDITION. Maintain Borrower's financial condition as
follows, determined in accordance with GAAP applied on a consistent basis
throughout the period involved except to the extent modified by the following
definitions:


         (i) Maintain a ratio of Total Liabilities to Tangible Net Worth of not
      more than 2.00 to 1.0. for each fiscal quarter beginning June 30, 1999 and
      each quarter thereafter.

         (ii) Maintain a ratio of Earnings before Interest Expense and Taxes
      divided by Interest Expense of not less than 2.5 to 1.0 calculated for the
      twelve month period ending December 31, 1998 and thereafter, measured
      annually.


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         B. FINANCIAL STATEMENTS AND OTHER INFORMATION. Maintain a system of
accounting satisfactory to Bank and in accordance with GAAP applied on a
consistent basis throughout the period 'Involved, permit Bank's officers or
authorized representatives to visit and inspect Borrower's books of account and
other records at such reasonable times and as often as Bank may desire, and pay
the reasonable fees and disbursements of any accountants or other agents of Bank
selected by Bank for the foregoing purposes. Unless written notice of another
location .is given to Bank, Borrower's books and records will be located at
Borrower's chief executive office set forth above. All financial statements
called for below shall be prepared in form and content acceptable to Bank and by
independent certified public accountants acceptable to Bank.

In addition, Borrower will:

      (i). Furnish to Bank AUDITED financial statements of Borrower for each
fiscal year of Borrower, within 90 days after the close of each such fiscal
year.

      (ii). Furnish to Bank SELF PREPARED financial statements attested by an
officer of the Borrower (including a balance sheet and profit and loss
statement) for each quarter end of each fiscal year of Borrower, within 45 days
after the close of each such period.

      (iii). Furnish to Bank a compliance certificate, "Exhibit A", for (and
executed by an authorized representative of) Borrower, concurrently with and
dated as of the date of delivery of each of the financial statements as required
in paragraphs (i) and (ii) above, containing (a) a certification that the
financial statements of even date are true and correct and that the Borrower is
not in default under the terms of this Agreement, and (b) computations and
conclusions, in such detail as Bank may request, with respect to compliance with
this Agreement, and the other Loan Documents, including computations of all
quantitative covenants.

      (iv). Furnish to Bank promptly such additional information, reports and
statements respecting the business operations and financial condition of
Borrower as Bank may reasonably, request, from time to time, including but not
limited to:

      A current status report in a form satisfactory to the Bank, including
      listing of new contracts or installations added during the period,
      including the name of the contracting officer at the agency, each
      certified by an officer of the Borrower within 45 days of each fiscal
      quarter end.

      An aging of all accounts receivable, submitted quarterly within 45 days of
      each fiscal quarter end,

         C. INSURANCE. Maintain insurance with responsible insurance companies
on such of its properties, in such amounts and against such risks as is
customarily maintained by similar businesses operating in the same vicinity,
specifically to include fire and extended coverage insurance covering all
assets, business interruption insurance, workers compensation insurance and
liability insurance.

         D. EXISTENCE AND COMPLIANCE. Maintain its existence, good standing and
qualification to do business, where required and comply with all laws,
regulations and governmental requirements including, without limitation,
environmental laws applicable to it or to any of its property, business
operations and transactions.

         E. ADVERSE CONDITIONS OR EVENTS. Promptly advise Bank in writing of (1)
any condition, event or act which comes to Its attention that would or might
materially adversely affect Borrower's financial condition or operations, the
Collateral, or Bank's rights under the Loan Documents, (ii) any litigation in
which the claim against the Borrower assets and property exceed $1,000,000.00.
filed by or against Borrower, (iii) any event that has occurred that would
constitute an event of default under any Loan Documents and (iv) any uninsured
or partially uninsured loss through fire, theft, liability or property damage in
excess of an aggregate of $1,000,000.

         F. TAXES AND OTHER OBLIGATIONS. Pay all of its taxes, assessments and
other obligations, including, but not limited to taxes, costs or other expenses
arising out of this transaction, as the same become due and payable, except to
the extent the same are being contested in good faith by appropriate proceedings
in a diligent manner.


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         G. MAINTENANCE. Maintain all of its tangible property in good condition
and repair and make all necessary, replacements thereof, and preserve and
maintain all licenses, trademarks, privileges, permits,franchises, certificates
and the like necessary for the operation of its business.

         H. NOTIFICATION OF ENVIRONMENTAL CLAIMS. Borrower shall immediately
advise Bank in writing of any and all enforcement, cleanup, remedial, removal,
or other governmental or regulatory actions instituted, completed or threatened
pursuant to any applicable federal, state, or local laws, ordinances or
regulations relating to any Hazardous Materials affecting Borrower's business
operations, and (ii) all claims made or threatened by any third party against
Borrower relating to damages, contribution, cost recovery, compensation, loss or
Injury resulting from any Hazardous Materials. Borrower shall immediatelv notify
Bank of any remedial action taken by Borrower with respect to Borrower's
business operations.

         5. NEGATIVE COVENANTS. Until full payment and performance of all
obligations of Borrower under the Loan Documents. Borrower will not, without the
prior written consent of Bank (and without limiting any requirement of any other
Loan Documents):

         A. TRANSFER OF ASSETS OR CONTROL. Sell, lease, assign or otherwise
dispose of or transfer any assets, except in the normal course of its business,
or enter into any merger or consolidation, or transfer control or ownership of
the Borrower or from or acquire any subsidiary.

         B. LIENS. Grant, suffer or permit any contractual or noncontractual
lien on or security interest in its assets, except in favor of Bank, or purchase
money obligations, in excess of $500,000.00, for capital expenditures or fail to
promptly pay when due all lawful claims, whether for labor, materials or
otherwise,

         C. ADVANCES. Make any advances, except in the ordinary course of
business, to any individual, partnership, corporation or other entity.

         D. BORROWINGS. Create, incur, assume or become liable in any manner for
any indebtedness (for borrowed money, deferred payment for the purchase of
assets, lease payments, as surety or guarantor for the debt for another, or
otherwise) other than to Bank, in excess of $500,000.00, except for normal trade
debts incurred in the ordinary course of Borrower's business, and except for
existing indebtedness disclosed to Bank in writing and acknowledged by Bank
prior to the date of this Agreement.

         E. PURCHASE OF CAPITAL STOCK. Purchase, redeem or retire any of its
capital stock in excess of $500.000 in the aggregate per annum, or make any
other distribution of property in respect of the Borrower's stock.

         F. LOANS. Make any loan to any person, firm or corporation or to their
employees, officers, directors. or stockholders in excess of $25O,000.00 in the
aggregate.

         G. GUARANTEES AND ENDORSEMENTS. Assume, guarantee, endorse, lease, or
otherwise become liable on the obligations of any person. firm, or corporation:
except by endorsement, for the purpose of discount or collection. of notes or
other instruments received by the Borrower from customers in the ordinary course
of its business.

         H. PLEDGES. Pledge, mortgage, encumber, lease, or sell any of its
assets except in the ordinary course of business and for permitted fixed assets
purchases and leases not to exceed $500,000.00.

         I. MERGER AND CONSOLIDATIONS. Be party to any acquisition, merger or
consolidation, or sell or transfer all, or substantially all, their property, to
any person, firm or corporation.

         J. CHARACTER OF BUSINESS. Change the general character of business as
conducted at the date hereof, or engage in any type of business not reasonably
related to its business as presently conducted.


<PAGE>


         K. 0WNERSHIP. David Karlgaard, Paul Rice and Alan Harbitter shall not
decrease their ownership percentage below 51 % of issued shares and voting
control in the Company in the aggregate and shall not pledge, assets encumber or
cause to be pledged any such ownership or voting control

         L. MANAGEMENT. Change the current management of the Borrower without
prior consent from the Bank.


      6. SECURITY DOCUMENTATION. On or before the Closing Date the Bank shall
have received:

         (a) duly executed and delivered copies of the guarantees, security
agreement, note and all other required documents.

         (b) evidence satisfactory to the Bank of the completion of all
recordings, registrations and filings as may be necessary or in the opinion of
the Bank, desirable to perfect or preserve the security interests created by the
security agreement, including without limitation, copies of proper financing
statements on Form UCC-1 duly filed in all jurisdictions as may be necessary or.
in the opinion of the Bank, desirable to perfect the security interests created
by the security agreement.

      7. DEFAULT. Borrower shall be in default under this Agreement and under
each of the other Loan Documents if it shall default in the payment of any
amounts due and owing under the Loans or should it fall to timely and properly
observe, keep or perform any term, covenant, agreement or condition in any Loan
Document or in any other loan agreement, promissory note, security agreement,
deed of trust, deed to secure debt, mortgage, assignment or other contract
securing or evidencing payment of any indebtedness of Borrower to Bank or any
affiliate or subsidiary of Nations Bank Corporation.

      8. REMEDIES UPON DEFAULT. If an event of default shall occur Bank shall
have all rights, powers and remedies available under each of the Loan Documents
as well as all rights and remedies available at law or in equity.

      9. NOTICES. All notices, requests or demands which any party is required
or may desire to give to any other party under any provision of this Agreement
must be in writing delivered to the other party at the following address:

     BORROWER:
     Performance Engineering Corporation
     David Karlgaard, President
     3949 Pender Drive
     Suite 300
     Fairfax, VA 22030

     BANK:
     NationsBank, N.A.
     Commercial Department - Government Contracts & Technology Banking Group
     Elaine Eaton, Senior Vice President
     8300 Greensboro Dr. Suite 550
     McLean, VA 22102

or to such other address as any party may designate by written notice to the
other party. Each such notice, request and demand shall be deemed given or made
as follows:

     A. If sent by hand delivery, upon delivery,


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     B. If sent by mail, upon the earlier of the date of receipt or five (5)
days after deposit in the U.S. Mail, first class postage prepaid.

     10. COSTS, EXPENSES AND ATTORNEY'S FEES. Borrower shall pay to Bank
immediately upon demand the full amount of all costs and expenses, including
reasonable attorneys' fees (to include outside counsel fees and all allocated
costs of Bank's in-house counsel if permitted by applicable law), incurred by
Bank in connection with (a) negotiation and preparation of this Agreement and
each of the Loan Documents, and (b) Bank's continued administration and
collection thereof.

     11. CONDITIONS OF EACH ADVANCE/CONDITIONS ANTECEDENT. Each time the
Borrower requests an advance under the Revolving Line of Credit, the Borrower
will provide a Borrowing Base Certificate, containing a list of the book
value of the Borrower's eligible accounts receivable, unless the last
Borrowing Base Certificate submitted is less than 30 days old.
Notwithstanding the maximum amount of the Loan, the total of advances
outstanding under the Loan at any time shall not exceed an amount equal to
the sum of 80% of the book value of Borrower's eligible accounts receivable.

     12. MISCELLANEOUS. Borrower and Bank further covenant and agree as follows,
without limiting any requirement of any other Loan Document:

         A. CUMULATIVE RIGHTS AND NO WAIVER. Each and every right granted to
Bank under any Loan Document, or allowed it by law or equity shall be cumulative
of each other and may be exercised in addition to any and all other rights of
Bank, and no delay in exercising any right shall operate as a waiver thereof,
nor shall any single or partial exercise bv Bank of any right preclude any other
or future exercise thereof or the exercise of any other right. Borrower
expressly ,waives any presentment, demand, protest or other notice of any kind,
including but not limited to notice of intent to accelerate and notice of
acceleration. No notice to or demand on Borrower in any case shall, of itself,
entitle Borrower to any other or future notice or demand in similar or other
circumstances.

         B. APPLICABLE LAW. This Loan Agreement and the rights and obligations
of the parties hereunder shall be governed by and interpreted in accordance with
the laws of Virginia and applicable United States federal law.

         C. AMENDMENT. No modification, consent, amendment or waiver of any
provision of this Loan Agreement, nor consent to any departure by Borrower
therefrom, shall be effective unless the same shall be in writing and signed by
an officer of Bank, and then shall be effective only in the specified instance
and for the purpose for which given. This Loan Agreement is binding upon
Borrower, its successors and assigns, and inures to the benefit of Bank, its
successors and assigns; however, no assignment or other transfer of Borrower's
rights or obligations hereunder shall be made or be effective without Bank's
prior ,written consent, nor shall it relieve Borrower of any obligations
hereunder. There is no third party beneficiary of this Loan Agreement.

         D. DOCUMENTS. All documents, certificates and other items required
under this Loan Agreement to be executed and/or delivered to Bank shall be in
form and content satisfactory to Bank and its counsel.

         E. PARTIAL INVALIDITY. The unenforceability or invalidity, of any
provision of this Loan Agreement shall not affect the enforceability or validity
of any other provision herein and the invalidity or unenforceability of any
provision of any Loan Document to any person or circumstance shall not affect
the enforceability or validity, of such provision as it may apply to other
persons or circumstances.

         F. INDEMNIFICATION. Borrower shall indemnify, defend and hold Bank and
its successors and assigns harmless from and against any and all claims.
demands, suits. losses, damages, assessments, fines, penalties, costs or other
expenses including reasonable attorneys' fees and court costs) arising from or
in any way related to any of the transactions contemplated hereby, including but
not limited to actual or threatened damage to the environment, agency costs of
investigation, personal injury or death, or property damage, due to a release or
alleged release of Hazardous Materials, arising from Borrower's business
operations, any other property owned by Borrower or in the surface or ground
water arising from Borrower's business operations, or gaseous emissions arising
from Borrower's business operations or any other condition existing or arising
from Borrower's business operations resulting from



<PAGE>


the use or existence of Hazardous Materials, whether such claim proves to be
true or false. Borrower further agrees that its indemnity obligations shall
include, but are not limited to, 1iability for damages resulting from the
personal injury or death of an employee of the Borrower, regardless of whether
the Borrower has paid the employee under the workmen' s compensation laws of any
state or other similar federal or state legislation for the protection of
employees. The term "property damage" as used in this paragraph includes. but is
not limited to, damage to any real or personal property of the Borrower, the
Bank, and of any third parties. The Borrower's obligations under this paragraph
shall survive the repayment of the Loan and any deed in lieu of foreclosure or
foreclosure of any Deed to Secure Debt, Deed of Trust, Security Agreement or
Mortgage securing the Loan.

         G. SURVIVABILITY. All covenants, agreements, representations and
warranties made herein or in the other Loan Documents shall survive the making
of the Loan and shall continue in full force and effect so long as the Loan is
outstanding or the obligation of the Bank to make any advances under the Line
shall not have expired.

     13.ARBITRATION. ANY CONTROVERSY OR CLAIM BETWEEN OR AMONG THE PARTIES
HERETO INCLUDING BUT NOT LIMITED TO THOSE ARISING OUT OF OR RELATING TO THIS
AGREEMENT OR ANY RELATED AGREEMENTS OR INSTRUMENTS, INCLUDING ANY CLAIM BASED ON
OR ARISING FROM AN ALLEGED TORT, SHALL BE DETERMINED BY BINDING ARBITRATION IN
ACCORDANCE WITH THE FEDERAL ARBITRATION ACT. (OR IF NOT APPLICABLE, THE
APPLICABLE STATE LAW). THE RULES OF PRACTICE AND PROCEDURE FOR THE ARBITRATION
OF COMMERCIAL DISPUTES OF JUDICIAL ARBITRATION AND MEDIATION SERVICES, INC.
(J.A.M.S.) AND THE "SPECIAL RULES" SET FORTH BELOW. IN THE EVENT OF ANY
INCONSISTENCY, THE SPECIAL RULES SHALL CONTROL. JUDGMENT UPON ANY ARBITRATION
AWARD MAY BE ENTERED IN ANY COURT HAVING JURISDICTION. ANY PARTY TO THIS
AGREEMENT MAY BRING AN ACTION, INCLUDING A SUMMARY OR EXPEDITED PROCEEDING, TO
COMPEL ARBITRATION OF ANY CONTROVERSY OR CLAIM TO WHICH THIS AGREEMENT APPLIES
IN ANY COURT HAVING JURISDICTION OVER SUCH ACTION.

         (A) SPECIAL RULES. THE ARBITRATION SHALL BE CONDUCTED IN THE CITY OF
THE BORROWER'S DOMICILE AT THE TIME OF THIS AGREEMENT'S EXECUTION AND
ADMINISTERED BY THE JUDICIAL ARBITRATION & MEDIATION SERVICES ("JAMS") OFFICE,
WHO WILL APPOINT AN ARBITRATOR, IF J.A.M.S. IS UNABLE OR LEGALLY PRECLUDED FROM
ADMINISTRATING THE ARBITRATION, THEN THE AMERICAN ARBITRATION ASSOCIATION
("AAA") WILL SERVE. ALL ARBITRATION WILL BE COMMENCED WITHIN 90 DAYS OF THE
DEMAND FOR ARBITRATION; FURTHER, THE ARBITRATOR SHALL, ONLY UPON A SHOWING OF
CAUSE, BE PERMITTED TO EXTEND THE COMMENCEMENT PERIOD FOR AN ADDITIONAL 60 DAYS.

         (B) RESERVATION OF RIGHTS. NOTHING IN THIS AGREEMENT SHALL BE DEEMED TO
(I) LIMIT THE APPLICABILITY OF ANY APPLICABLE STATUTES OF LIMITATION OR REPOSE
OR ANY WAIVERS CONTAINED IN THIS AGREEMENT; OR (II) BE A WAIVER BY THE BANK OF
THE PROTECTION AFFORDED TO IT BY 12 U.S.C. 91 OR ANY SUBSTANTIALLY EQUIVALENT
STATE LAW- OR (III) LIMIT THE RIGHT OF THE BANK HERETO (A) TO EXERCISE SELF HELP
REMEDIES SUCH AS (BUT NOT LIMITED TO) SETOFF. OR (B) TO FORECLOSE AGAINST ANY
REAL OR PERSONAL PROPERTY COLLATERAL, OR (C) TO OBTAIN FROM A COURT PROVISIONAL
OR ANCILLARY REMEDIES SUCH AS (BUT NOT LIMITED TO) INJUNCTIVE RELIEF, WRIT OF
POSSESSION OR THE APPOINTMENT OF A RECEIVER. THE BANK MAY EXERCISE SUCH SELF
HELP RIGHTS, FORECLOSE UPON SUCH PROPERTY, OR OBTAIN SUCH PROVISIONAL OR
ANCILLARY REMEDIES BEFORE, DURING OR AFTER THE PENDENCY OF ANY ARBITRATION
PROCEEDING BROUGHT PURSUANT TO THIS AGREEMENT. NEITHER THE EXERCISE OF SELF HELP
REMEDIES NOR THE INSTITUTION OR MAINTENANCE OF AN ACTION FOR FORECLOSURE OR
PROVISIONAL OR ANCILLARY REMEDIES SHALL CONSTITUTE A WAIVER OF THE RIGHT OF ANY
PARTY, INCLUDING THE CLAIMANT IN ANY SUCH ACTION, TO ARBITRATE THE MERITS OF THE
CONTROVERSY OR CLAIM OCCASIONING RESORT TO SUCH REMEDIES.


<PAGE>


     14. NO ORAL AGREEMENT. THIS WRITTEN AGREEMENT AND THE OTHER LOAN
DOCUMENTS REPRESENT THE FINAL AGREEMENT BETWEEN THE PARTIES AND MAY NOT BE
CONTRADICTED BY EVIDENCE OF PRIOR, CONTEMPORANEOUS OR SUBSEQUENT ORAL
AGREEMENTS OF THE PARTIES. THERE ARE NO ORAL AGREEMENTS BETWEEN THE PARTIES.

<PAGE>



     IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
duly executed under seal by their duly authorized representatives as of the date
first above written.

BORROWER: PERFORMANCE ENGINEERING CORPORATION     BANK: NATIONSBANK, N.A.

By: /s/ STUART LLOYD  (Seal)                      By: /s/ ELAINE EATON
    ---------------                                   ----------------
    Stuart Lloyd                                  Elaine Eaton
    Chief Financial Officer                       Senior Vice President

    [Corporate Seal]

If the Borrower is a corporation, the signature should be attested by the
Secretary or Assistant Secretary of the corporation and corporate seal affixed.

Attest: /s/ ALAN HARBITTER (Seal)
        ------------------
Name: Alan Harbitter
Title: Secretary



<PAGE>




                                    Exhibit A

                             COMPLIANCE CERTIFICATE

      This Compliance Certificate is delivered pursuant to Section 4(B)(iii) of
the Amended and Restated Loan Agreement dated as of April 30, 1999 (together
with all amendments and modifications, if any, from time to time made thereto,
the "Agreement"), between Performance Engineering Corporation (the "Borrower")
and NationsBank, N.A. Unless otherwise defined, terms used herein (including the
attachments hereto) have the meanings provided in the Loan Agreement.

      The undersigned, being the duly elected, qualified and acting of the
Borrower, on behalf of the Borrower and solely in hi, or her capacity as an
officer of the Borrower, hereby certifies and warrants that:

      1.   He or she is the             of the Borrower and that,as such, he or
           she, is authorized to execute this certificate on behalf of th
           Borrower.

      2.        As of                       . 19     :

           (a)  The Borrower was not in default of any of the provisions of the
                Loan Agreement during the period as to which this Compliance
                Certificate relates,

           (b)  Borrower's ratio of Total Liabilities to Tangible Net Worth was
                to 1.0 as computed on Attachment 1 hereto,

           (c)  Borrower's Earnings before Interest Expense and Taxes divided by
                Interest Expense ratio was to 1.0 as computed on Attachment 1
                hereto; and

      3.    The Borrower's loans to employees for the period ending was $
        as computed on Attachment 1 hereto.

      4.       The Borrower's capital stock repurchases for the period ending
                     was $     as computed on Attachment 1 hereto.

      5.       The Borrower's Indebtedness incurred for fixed assets for the
               period ending      was $     as computed on Attachment 1 hereto.

      6.    The Borrower's Pledges on fixed assets for the period ending     was
         $     as computed on Attachment 1 hereto.


    IN WITNESS WHEREOF, the undersigned has executed and delivered this
    certificate,this day of       19.

                                         PERFORMANCE ENGINEERING CORPORATION

                                          By:

                                          Title:


<PAGE>



                                  ATTACHMENT 1

Period ending

RATIO OF TOTAL LIABILITIES TO TANGIBLE NET WORTH

      1.        Total Liabilities:                $

      2.        Tangible Net Worth:               $

Ratio:Total liabilities to Tangible Net Worth (1/2)= to 1.0 required Ratio: 2.00
to 1.0

Measured quarterly

CASH FLOW COVERAGE RATIO
1. Aggregate of earnings before interest expense and taxes      $       .  2.
Interest Expense:                               $
Ratio 1/2            to 1.0            Required Ratio: 2.5 to 1.0

Measured annually at year-end
LOANS
    1. Maximum aggregate loans shall not to exceed $250,000.00.
       MAXIMUM YEAR TO DATE

ADDITIONAL INDEBTEDNESS
    1. Maximum aggregate debt for fixed assets shall not to exceed $500,000.00.
       MAXIMUM YEAR TO DATE                     $

PLEDGE OF ASSETS
    1 .Maximum aggregate pledge against fixed assets not to exceed $500,000.00.
       MAXIMUM YEAR TO DATE                     $

CAPITAL STOCK REPURCHASE
    1 .Maximum aggregate annual stock repurchase not to exceed $500,000
       MAXIMUM YEAR TO DATE                      $