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                                                                    Exhibit 4.9b


                       MODIFICATION AND CONSENT AGREEMENT

         BY THIS MODIFICATION AND CONSENT AGREEMENT (the "Agreement"), made and
entered into effective September 15, 1999, SIMULA, INC., an Arizona corporation
(the "Company") and SIEGLER & CO. (NORTHSTAR HIGH TOTAL RETURN FUND --
CUSTODIAN) ("Noteholder"), in consideration of the mutual covenants herein
contained and other good and valuable consideration, the receipt and sufficiency
of which is hereby acknowledged, hereby confirm and agree as follows:

                                    RECITALS

         A. Noteholder holds Simula, Inc. Series C 10% Senior Subordinated
Convertible Notes Nos. 16 through 32 in an aggregate principal amount of Four
Million Two Hundred Fifty Thousand Dollars ($4,250,000) (the "Notes") issued
pursuant to an indenture dated December 17, 1993, as amended and supplemented,
by and among Simula, Inc. as Issuer, Subsidiary Guarantors as Guarantors, and
BankOne Trust Company NA as Trustee (the "Indenture").

         B. The Notes mature on September 15, 1999.

         C. The accrued interest due and payable on September 15, 1999 has been
paid to Noteholder.

         D. Noteholder and the Company wish to modify the Notes as set forth
herein.

                                    AGREEMENT

SECTION 1. ACCURACY OF RECITALS.

         The Company and Noteholder acknowledge the accuracy of the Recitals.

SECTION  2. DEFINED TERMS.

         All capitalized terms not otherwise defined herein shall have the
meaning assigned to them in the Indenture.

SECTION  3. MODIFICATION OF THE NOTES.

         The Notes are modified as follows:

         (a) Maturity Date. The Maturity Date is extended to October 31, 1999.

         (b) Interest Rate. Interest is payable at a rate of fifteen percent
(15%) per annum from September 15, 1999 until the Maturity Date.

         (c) Required Modifications. The Notes and the corresponding provisions
of the Indenture are hereby amended consistent with the above modifications.

SECTION  4. CONSENT TO AMENDMENT OF INDENTURE.

         To effect the modification of the Notes, Noteholder, who represents a
majority in principal amount of all notes issued by Simula, Inc. pursuant to the
Indenture, hereby consents to the modifications and amendment set out in Section
3 above in the form of Amendment No. 2 to Supplement No. 2 of the Indenture.
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SECTION 5. NO OTHER CHANGES; INTEGRATION, ENTIRE AGREEMENT, CHANGE, DISCHARGE,
           TERMINATION, OR WAIVER.

         The Notes as modified herein contain the complete understanding and
agreement of the Company and Noteholder and supersede all prior representations,
warranties, agreements, arrangements, understandings, and negotiations. Except
as expressly modified herein, no other changes are made to the Notes or the
Indenture. No provision of the Notes as modified herein may be changed,
discharged, supplemented, terminated, or waived except in a writing signed by
the parties thereto.

SECTION  5. CHOICE OF LAW; JURISDICTION.

         This Agreement shall be governed by and construed in accordance with
the laws of the State of Arizona, without giving effect to conflicts of laws
principles. Any dispute arising under this Agreement shall be brought in a court
of competent jurisdiction located within the State of Arizona.

         DATED as of the date first above stated.

                                      SIMULA, INC., an Arizona corporation


                                      By       /s/  James C. Dodd
                                         ---------------------------------------
                                      Its      Chief Financial Officer
                                         ---------------------------------------

                                      SIEGLER & CO. (NORTHSTAR HIGH TOTAL RETURN
                                      FUND -- CUSTODIAN)


                                      By       /s/  Robert T. Claiborne
                                         ---------------------------------------
                                      Its      Vice President
                                         ---------------------------------------