Exhibit 4.1

SUPPLEMENTAL INDENTURE

SUPPLEMENTAL INDENTURE (this “Supplemental Indenture”), dated as of June 22, 2010, among DynCorp International LLC (the “Company”), DIV Capital Corporation (the “Co-Issuer,” and collectively with the Company, the “Issuers”), the Guarantors (as defined in the Indenture referred to herein) and The Bank of New York Mellon, as trustee under the Indenture referred to below (the “Trustee”). Capitalized terms used herein without definition shall have the meanings assigned to them in the Indenture.

W I T N E S S E T H

WHEREAS, the Issuers and the Guarantors have heretofore executed and delivered to the Trustee an indenture (as amended, supplemented or otherwise modified, the “Indenture”), dated as of February 11, 2005, providing for the issuance of the Issuers’ 9.50% Senior Subordinated Notes due 2013 (the “Notes”);

WHEREAS, pursuant to Section 9.02 of the Indenture, the Company and the Trustee are authorized to execute and deliver this Supplemental Indenture with the written consents (the “Consents”) from Holders of a majority in principal amount of the Notes then outstanding, voting as a single class (including consents obtained in connection with a tender offer for the Notes) (the “Required Consents”);

WHEREAS, the Company has offered to purchase for cash (the “Offer”) any and all of the outstanding Notes upon the terms and subject to the conditions set forth in the Offer to Purchase and Consent Solicitation Statement, dated June 7, 2010 (as it may be amended or supplemented from time to time, the “Offer to Purchase”);

WHEREAS, in connection with the Offer, the Company has solicited consents from Holders to the amendments contained herein (collectively, the “Proposed Amendments”) and the execution of this Supplemental Indenture; and

WHEREAS, the Company has received Consents to the Proposed Amendments and the execution of this Supplemental Indenture from Holders of $374,112,000, or 99.44%, of the principal amount of the Notes (including, without limitation, Additional Notes) outstanding, voting as a single class and calculated in accordance with the Indenture, and accordingly the Company has received the Required Consents.

NOW, THEREFORE, in consideration of the foregoing and for other good and valuable consideration, the receipt of which is hereby acknowledged, the Issuers, the Guarantors and the Trustee, mutually covenant and agree for the equal and ratable benefit of the Holders of the Notes as follows:

“Effective as of the Amendment Effective Time (as defined in Supplemental Indenture dated June 22, 2010 to this Indenture copies of which are on file with the Trustee), substantially all of the restrictive covenants and certain of the events of default and related provisions have been eliminated from the Indenture.”

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IN WITNESS WHEREOF, the parties hereto have caused this Supplemental Indenture to be duly executed and attested, all as of the date first above written.