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                                  Exhibit 10.24
                                 AMENDMENT NO. 4

                          Dated as of October 15, 1999

                                       to

                      AMENDED AND RESTATED CREDIT AGREEMENT

                           Dated as of March 19, 1998

                  THIS AMENDMENT NO. 4 ("Amendment") is made as of October 15,
1999 by and among IFR SYSTEMS, INC. (the "Borrower"), the financial institutions
parties hereto as Lenders, and BANK ONE, NA, formerly known as THE FIRST
NATIONAL BANK OF CHICAGO, in its capacity as contractual representative (the
"Agent") under that certain Amended and Restated Credit Agreement dated as of
March 19, 1998 by and among the Borrower, the Lenders and the Agent, as amended
by an Amendment No. 1 and Waiver dated as of November 3, 1998, an Amendment No.
2 dated as of March 31, 1999, and an Amendment No. 3 dated as of June 25, 1999
(as amended and as the same may be amended, restated, supplemented or otherwise
modified from time to time, the "Credit Agreement"). Defined terms used herein
and not otherwise defined herein shall have the respective meanings given to
them in the Credit Agreement.

                  WHEREAS, the Borrower, the Lenders and the Agent are parties
to the Credit Agreement; and

                  WHEREAS, the Borrower has requested that the Agent and the
Required Lenders amend the Credit Agreement in certain respects, and the
Required Lenders and the Agent are willing to amend the Credit Agreement on the
terms and conditions set forth herein, it being expressly understood that the
modifications set forth herein shall in no event constitute a waiver by the
Lenders or the Agent of any breach of the Credit Agreement or any of the
Lenders' or Agent's rights or remedies with respect thereto;

                  NOW, THEREFORE, in consideration of the premises set forth
above, the terms and conditions contained herein, and other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, the
Borrower, the Lenders and the Agent have agreed to the following amendments to
the Credit Agreement:

                  1. AMENDMENT TO CREDIT AGREEMENT. Effective as of the
Effective Date (as defined below) and subject to the satisfaction of the
conditions precedent set forth in SECTION 2 below, the Credit Agreement is
hereby amended as follows:

                  1.1      SECTION 1.1 of the Credit Agreement is amended to
insert the following immediately prior to the period (".") now appearing at the
end of the definition of "EBITDA":

         ", PLUS (xi) any non-recurring restructuring charges incurred in fiscal
         year 1999 related to payment of severance to employees of the Borrower
         up to $2,000,000 in the aggregate to the extent deducted in computing
         Net Income".

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                  2. CONDITIONS OF EFFECTIVENESS. The effectiveness of this
Amendment is subject to the condition precedent that the Agent shall have
received the following documents:

                  (i)      duly executed originals of this Amendment from the
                           Borrower, the Required Lenders and the Agent;

                  (ii)     duly executed originals of the Reaffirmation attached
                           hereto from each Domestic Incorporated Subsidiary of
                           the Borrower; and

                  (iii)    such other documents, instruments and agreements as
                           the Agent may reasonably request.

Upon the satisfaction of the foregoing conditions precedent, this Amendment
shall be deemed effective as of October 15, 1999 (the "Effective Date").

                  3. REPRESENTATIONS AND WARRANTIES OF THE BORROWER. The
Borrower hereby represents and warrants as follows:

                  (a) This Amendment and the Credit Agreement as previously
executed and as amended hereby, constitute legal, valid and binding obligations
of the Borrower and are enforceable against the Borrower in accordance with
their terms.

                  (b) Upon the effectiveness of this Amendment, the Borrower
hereby reaffirms all covenants, representations and warranties made in the
Credit Agreement, as amended hereby, and agrees that all such covenants,
representations and warranties shall be deemed to have been remade as of the
Effective Date of this Amendment.

                  4. REFERENCE TO AND EFFECT ON THE CREDIT AGREEMENT.

                  (a) Upon the effectiveness of SECTION 1 hereof, each reference
to the Credit Agreement in the Credit Agreement and each other Loan Document
shall mean and be a reference to the Credit Agreement as amended hereby.

                  (b) Except as specifically amended above, the Credit Agreement
and all other documents, instruments and agreements executed and/or delivered in
connection therewith shall remain in full force and effect and are hereby
ratified and confirmed.

                  (c) The execution, delivery and effectiveness of this
Amendment shall not operate as a waiver of any right, power or remedy of the
Agent or the Lenders, nor constitute a waiver of any provision of the Credit
Agreement or any other documents, instruments and agreements executed and/or
delivered in connection therewith.

                  5. GOVERNING LAW. THIS AMENDMENT SHALL BE GOVERNED BY AND
CONSTRUED IN ACCORDANCE WITH THE INTERNAL LAWS (INCLUDING, WITHOUT LIMITATION,
735 ILCS 105/5-1 ET SEQ., BUT OTHERWISE WITHOUT REGARD TO THE CONFLICTS OF LAWS
PROVISIONS) OF THE STATE OF ILLINOIS.


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                  6. HEADINGS. Section headings in this Amendment are included
herein for convenience of reference only and shall not constitute a part of this
Amendment for any other purpose.

                  7. COUNTERPARTS. This Amendment may be executed by one or more
of the parties to the Amendment on any number of separate counterparts, and all
of said counterparts taken together shall be deemed to constitute one and the
same instrument.


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                  IN WITNESS WHEREOF, this Amendment has been duly executed as
of the day and year first above written.

                        IFR SYSTEMS, INC.


                        By: ____________________________
                              Name:
                              Title:


                        BANK ONE, NA, FORMERLY KNOWN AS THE FIRST
                        NATIONAL BANK OF CHICAGO, as Agent and as Lender


                        By: ____________________________
                              Name:
                              Title:


                        INTRUST BANK, as a Lender


                        By: ____________________________
                              Name:
                              Title:


                        THE BANK OF NOVA SCOTIA, as a Lender

                        By: ____________________________
                              Name:
                              Title:


                        HARRIS TRUST AND SAVINGS BANK, as a Lender

                        By: ____________________________
                              Name:
                              Title:


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                        NATIONAL WESTMINSTER BANK PLC, as a Lender


                        By: ____________________________
                              Name:
                              Title:


                        UNION BANK OF CALIFORNIA, N.A., as a Lender


                        By: ____________________________
                              Name:
                              Title:


                        LLOYDS TSB BANK PLC, as a Lender


                        By: ____________________________
                              Name:
                              Title:


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                                  REAFFIRMATION

                  Each of the undersigned hereby acknowledges receipt of a copy
of the foregoing Amendment No. 4 to the Amended and Restated Credit Agreement
dated as of March 19, 1998 by and among IFR Systems, Inc., a Delaware
corporation (the "Borrower"), the lenders from time to time parties thereto
(collectively, the "Lenders") and Bank One, NA, formerly known as The First
National Bank of Chicago, as one of the Lenders and in its capacity as
contractual representative (the "Agent") on behalf of itself and the other
Lenders, as amended by an Amendment No. 1 and Waiver and an Amendment No. 2
dated as of November 3, 1998 and March 31, 1999, respectively (as amended and as
the same may be amended, restated, supplemented or otherwise modified from time
to time, the "CREDIT AGREEMENT") which Amendment No. 4 is dated as of October
15, 1999 (the "AMENDMENT"). Capitalized terms used in this Reaffirmation and not
defined herein shall have the meanings given to them in the Credit Agreement.
Without in any way establishing a course of dealing by the Agent or any Lender,
each of the undersigned reaffirms the terms and conditions of the Guaranty,
Security Agreement and any other Loan Document executed by it and acknowledges
and agrees that such agreement and each and every such Loan Document executed by
the undersigned in connection with the Credit Agreement remains in full force
and effect and are hereby reaffirmed, ratified and confirmed. All references to
the Credit Agreement contained in the above-referenced documents shall be a
reference to the Credit Agreement as so modified by the Amendment and as the
same may from time to time hereafter be amended, modified or restated.

Dated:  October 15, 1999         IFR AMERICAS, INC., formerly known as IFR
                                            Instruments, Inc.
                                 PK TECHNOLOGY, INC.
                                 IFR INSTRUMENTS OF TEXAS, INC., formerly
                                            known as Marconi Instruments, Inc.
                                 IFR FINANCE, INC.

                                 By __________________________
                                      Name:
                                      Title:


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