<PAGE>
                                                                     EXHIBIT 4.7


                                 AMENDMENT NO. 2



        AMENDMENT NO. 2 (this "AMENDMENT"), dated as of September 30, 2001,
between J.H. Whitney Mezzanine Fund, L.P. (the "PURCHASER"), a Delaware limited
partnership, and Mercury Air Group, Inc., a Delaware corporation (the
"COMPANY"), to the Securities Purchase Agreement (the "PURCHASE AGREEMENT"),
dated as of September 10, 1999, between the Purchaser and the Company, as
amended by Amendment No. 1 dated as of September 30, 2000.


                              W I T N E S S E T H:

        WHEREAS, the Purchaser and the Company entered into the Purchase
Agreement (the Purchase Agreement, as amended by this Amendment, is hereinafter
referred to as the "AGREEMENT"), pursuant to which, among other things, the
Purchaser purchased from the Company (i) a subordinated promissory note due
September 9, 2006 in the principal amount of $24,000,000, and (ii) a warrant to
purchase 503,126 shares of common stock, $.01 par value per share, of the
Company; and

        WHEREAS, the Company has requested that WMF provide the waiver provided
for herein, and WMF has agreed to provide such waiver on the terms and
conditions set forth herein;


        WHEREAS, the Purchaser and the Company desire to amend the Purchase
Agreement to change the Interest Coverage ratio financial covenant and the Quick
Ratio financial covenant therein.

        NOW THEREFORE, in consideration of the premises set forth herein and for
other good and valuable consideration, the sufficiency and receipt of which is
hereby acknowledged, the Purchaser and the Company agree as follows:

                                    ARTICLE 1

                                   DEFINITIONS

        1.1 PURCHASE AGREEMENT DEFINITION. All capitalized terms used in this
Amendment but not defined shall have the meanings given to them in the Purchase
Agreement. In the event of a conflict between the definitions contained in this
Amendment and those contained in the Purchase Agreement, the definitions
contained herein shall prevail.

                                    ARTICLE 2

                                     WAIVER


        2.1 Pursuant to Section 9.8(a) of the Purchase Agreement, the Company
has agreed that it will not permit Interest Coverage for the Company and its
Subsidiaries, on a consolidated



<PAGE>

basis, for the twelve-month period ending on September 30, 2001 to be less than
4.00:1.00. The Company has advised WMF that as for the twelve month period ended
September 30, 2001, Interest Coverage covered for the Company and its
Subsidiaries, on a consolidated basis was 3.4:1.0, and has requested that WMF
waive compliance by the Company with the covenant set forth in Section 9.8(a).
Subject to the terms and provisions of this Amendment, WMF hereby waives
compliance by the Company and its Subsidiaries with the covenant set forth in
Section 9.8(a). This waiver is limited as specified and shall not constitute a
modification, acceptance or waiver of any other provision of the Purchase
Agreement or any of the other Transaction Documents.

                                   ARTICLE 3

                        AMENDMENTS TO PURCHASE AGREEMENT

        3.1 AMENDMENT TO SECTION 9.8(a).

                Section 9.8(a) of the Purchase Agreement is deleted in its
entirety and the following is substituted therefor:

                        INTEREST COVERAGE. The Company shall not permit Interest
                Coverage for the Company and its Subsidiaries, on a consolidated
                basis, for any twelve (12) month period ending on the last day
                of a fiscal quarter during any of the periods set forth below to
                be less than the ratio set forth below for such period:

<TABLE>
<CAPTION>
               Period                                                     Ratio
               ------                                                     -----
               <S>                                                     <C>
               Closing Date to and including June 30, 2000             3.125:1.00
               July 1, 2000 to and including December 31, 2000          2.75:1.00
               January 1, 2001 to and including March 31, 2001          3.25:1.00
               April 1, 2001 to and including June 30, 2001             3.50:1.00
               July 1, 2001 and thereafter                              3:25:1.00
</TABLE>

                        "INTEREST COVERAGE" shall be calculated as illustrated
                on Exhibit D.

        3.2 AMENDMENT TO SECTION 9.8(f).

                Section 9.8(f) of the Purchase Agreement is deleted in its
entirety and the following is substituted therefor:

                        QUICK RATIO. The Company will not permit the ratio of
                (i) Quick Assets to (ii) the sum of Current Liabilities and (B)
                to the extent not included in Current Liabilities, the aggregate
                outstanding amount of all Loans under the Senior Credit
                Documents (other than the Term Loan, the Acquisition Loans and
                obligations in respect of the Letters of Credit, all as such
                terms are defined in the Senior Credit Agreement) for the
                Company and its Subsidiaries on a consolidated basis during the
                periods set forth below to be less than the ratio set forth
                below for such period:




                                       2
<PAGE>

<TABLE>
<CAPTION>
               Period                                                  Ratio
               ------                                                  -----
               <S>                                                   <C>
               Closing Date to and including March 31, 2001          1.10:1.00
               April 1, 2001 to and including March 31, 2002         1.15:1.00
               April 1, 2002, and thereafter                         1.20:1.00
</TABLE>


                                    ARTICLE 4

                         REPRESENTATIONS AND WARRANTIES

        The Company represents and warrants to the Purchaser as follows:


        4.1 REPRESENTATIONS AND WARRANTIES IN THE PURCHASE AGREEMENT. The
representations and warranties of the Company contained in the Article 5 of the
Purchase Agreement were true, correct and complete as and when made.

        4.2 AUTHORITY, ETC. The execution and delivery by the Company of this
Amendment and the performance by the Company of all of its agreements and
obligations under this Amendment and the Agreement (i) are within the corporate
authority of the Company, (ii) have been duly authorized by all necessary
corporate proceedings by the Company, (iii) do not conflict with or result in
any breach or contravention of any provision of law, statute, rule or regulation
to which the Company is subject or any judgment, order, writ, injunction,
license or permit applicable to the Company, and (iv) do not conflict with any
provision of the corporate charter or by-laws of, or any agreement or other
instrument binding upon, the Company.

        4.3 ENFORCEABILITY OF OBLIGATIONS. This Amendment and the Agreement
constitute the legal, valid and binding obligations of the Company, enforceable
against it in accordance with their respective terms.

        4.4 NO DEFAULT. After giving effect to this Amendment and the amendment
to the Senior Credit Agreement contemplated hereby, no default or Event of
Default exists under the Agreement or the Note.

                                    ARTICLE 5

                             AFFIRMATION OF GUARANTY


        5.1 For purposes of the Guaranty, by their respective signatures below,
each Guarantor hereby consents and agrees to the entering into of this Amendment
and acknowledges and affirms that the Guaranty (as amended, modified or
supplemented prior to the date hereof) remains in full force and effect in
accordance with its terms on the date hereof and after giving effect to this
Amendment.


                                    ARTICLE 6

                           CONDITIONS TO EFFECTIVENESS

          The effectiveness of this Amendment is conditioned upon the:



                                       3
<PAGE>

                (a) receipt by the Purchaser of an original counterpart
signature to this Amendment, duly executed and delivered by the Company;

                (b) receipt by the Purchaser, in form and substance satisfactory
to it, of the evidence of all corporate approval necessary in connection with
this Amendment and the consummation of the transactions contemplated herein,
including, without limitation, the issuance of the Amended and Restated WMF
Warrant referred to in clause (d) below;

                (c) the Purchaser shall be satisfied that, after giving effect
to this Amendment, no default or Event of Default shall then exist;

                (d) the WMF Warrant shall have been amended to reduce the
Purchase Price to $5.50 per share, which amendment shall be effected by the
exchange of an Amended and Restated WMF Warrant in the form of Exhibit A to this
Amendment for the WMF Warrant originally issued to the Purchaser; and

                (e) receipt by the Company of all consents under the Senior
Credit Agreement required in connection with this Amendment and the consummation
of the transactions contemplated herein, including, without limitation, the
issuance of the Amended and Restated WMF Warrant.


                                    ARTICLE 7

                                  MISCELLANEOUS

        7.1 CONTINUED EFFECTIVENESS. Notwithstanding anything contained herein,
the terms of this Amendment are not intended to and do not serve to effect a
novation as to the Purchase Agreement. The parties hereto expressly do not
intend to extinguish the Purchase Agreement. Instead, it is the express
intention of the parties hereto to reaffirm the indebtedness created under the
Purchase Agreement (including, without limitation, the Note) and the other
documents contemplated thereby and to reaffirm the rights and obligations
contained therein. The Purchase Agreement as amended hereby and each of the
other documents contemplated thereby shall remain in full force and effect.
Except as herein amended, the Purchase Agreement shall remain unchanged and in
full force and effect, and is hereby ratified in all respects. All of the
representations, warranties and covenants contained in the Purchase Agreement
and this Amendment shall survive the execution and delivery of this Amendment.

        7.2 NOTICES. All notices, demands and other communications provided for
or permitted hereunder shall be made in writing and shall be by registered or
certified first-class mail, return receipt requested, telecopier, courier
service or personal delivery:

                (a)   if to the Purchaser:

                      J.H. Whitney Mezzanine Fund, L.P.
                      177 Broad Street



                                       4
<PAGE>

                      Stamford, Connecticut  06901
                      Telecopier No.: (203) 973-1422
                      Attention: Mr. James H. Fordyce
                                 Mr. Daniel J. O'Brien

                      with a copy to:

                      Morrison Cohen Singer & Weinstein, LLP
                      750 Lexington Avenue
                      New York, New York  10022
                      Telecopier No.: (212) 735-8708
                      Attention: David A. Scherl
                                 Jack Levy, Esq.

                      if to the Company:

                      Mercury Air Group, Inc.
                      5456 McConnel Avenue
                      Los Angeles, CA 90066
                      Telecopier No.: (310) 827-0650
                      Attention: Mr. Joseph A. Czyzyk
                                 Wayne J. Lovett, Esq.

                      with a copy to:

                      McBreen, McBreen & Kopko
                      20 North Wackes Drive, Suite 252
                      Chicago, IL 60606
                      Telecopier No.: (312) 332-2657
                      Attention: Frederick Kopko, Esq.


                All such notices and communications shall be deemed to have been
duly given: when delivered by hand, if personally delivered; when delivered by
courier, if delivered by commercial overnight courier service; if mailed, five
Business Days after being deposited in the mail, postage prepaid; and if
telecopied, when receipt is acknowledged.

        7.3 SUCCESSORS AND ASSIGNS; THIRD PARTY BENEFICIARIES. This Amendment
shall inure to the benefit of and be binding upon the successors and permitted
assigns of the parties hereto.

        7.4 REFERENCES. Any reference to the Purchase Agreement contained in any
notice, requisite, certificate, or other document executed concurrently with or
after the execution and delivery of this Amendment shall be deemed to include
the amendments contained in this Amendment unless the context shall otherwise
require.

        7.5 SIGNATURES; COUNTERPARTS. Telefacsimile transmissions of any
executed original document and/or retransmission of any executed telefacsimile
transmission shall be deemed to be the same as the delivery of an executed
original. At the request of any party hereto, the other



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<PAGE>

parties hereto shall confirm telefacsimile transmissions by executing duplicate
original documents and delivering the same to the requesting party or parties.
This Amendment may be executed in any number of counterparts and by the parties
hereto in separate counterparts, each of which when so executed shall be deemed
to be an original and all of which taken together shall constitute one and the
same agreement.

        7.6 HEADINGS. The headings in this Amendment are for convenience of
reference only and shall not limit or otherwise affect the meaning hereof.

        7.7 GOVERNING LAW. THIS AGREEMENT SHALL BE GOVERNED BY, CONSTRUED IN
ACCORDANCE WITH, AND ENFORCED UNDER, THE LAW OF THE STATE OF NEW YORK, WITHOUT
REGARD TO THE PRINCIPLES OF CONFLICTS OF LAW OF SUCH STATE (INCLUDING GIVING
EFFECT TO GOL SECTION 5-1401).

        7.8 SEVERABILITY. If any one or more of the provisions contained herein,
or the application thereof in any circumstance, is held invalid, illegal or
unenforceable in any respect for any reason, the validity, legality and
enforceability of any such provision in every other respect and of the remaining
provisions hereof shall not be in any way impaired, unless the provisions held
invalid, illegal or unenforceable shall substantially impair the benefits of the
remaining provisions hereof.

        7.9 CERTAIN EXPENSES. The Company will pay all expenses of the Purchaser
(including fees, charges and disbursements of counsel) in connection with this
Amendment.

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

                                       MERCURY AIR GROUP, INC.


                                       By:
                                          --------------------------------------
                                       Name: Randolph E. Ajer
                                       Title: Chief Financial Officer


                                       J.H. WHITNEY MEZZANINE FUND, L.P.

                                       By: Whitney GP, L.L.C.


                                       By:
                                          --------------------------------------
                                       Name:
                                       Title: A Managing Member



                  [SIGNATURE PAGE TO AMENDMENT NO. 2 AGREEMENT]



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<PAGE>

GUARANTORS:


MERCFUEL, INC.

By:
   ---------------------------------
Name: John Condie
Title: Chief Financial Officer


MAYTAG AIRCRAFT CORPORATION

By:
   ---------------------------------
Name: Randolph E. Ajer
Title: Treasurer


MERCURY AIR CARGO, INC.

By:
   ---------------------------------
Name: Randolph E. Ajer
Title: Treasurer


AEG FINANCE CORPORATION

By:
   ---------------------------------
Name: Randolph E. Ajer
Title: Treasurer


MERCURY AIR CENTERS, INC.
(F/K/A WOFFORD FLYING SERVICES, INC.)

By:
   ---------------------------------
Name: Randolph E. Ajer
Title: Treasurer


HERMES AVIATION, INC.

By:
   ---------------------------------
Name: Randolph E. Ajer
Title: Treasurer


VULCAN AVIATION, INC.

By:
   ---------------------------------
Name: Randolph E. Ajer
Title: Treasurer


                  [SIGNATURE PAGE TO AMENDMENT NO. 2 AGREEMENT]



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<PAGE>

JUPITER AIRLINE AUTOMATION SERVICES, INC.
(f/k/a RPA AIRLINES AUTOMATION SERVICES, INC.)

By:
   ---------------------------------
Name: Randolph E. Ajer
Title: Treasurer


MERCURY ACCEPTANCE CORPORATION

By:
   ---------------------------------
Name: Randolph E. Ajer
Title: Treasurer


EXCEL CARGO, INC.

By:
   ---------------------------------
Name: Randolph E. Ajer
Title: Treasurer













                  [SIGNATURE PAGE TO AMENDMENT NO. 2 AGREEMENT]




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