FIFTH SUPPLEMENTAL INDENTURE

Exhibit 4.2

FIFTH SUPPLEMENTAL INDENTURE

Dated as of June 24, 2009

among

GENERAL DYNAMICS CORPORATION

and

THE GUARANTORS

and

THE BANK OF NEW YORK MELLON

as Trustee

to the

INDENTURE

Dated as of August 27, 2001

Providing for the issuance of

1.800% Notes due 2011

THIS FIFTH SUPPLEMENTAL INDENTURE, dated as of June 24, 2009 (this “ Fifth Supplemental Indenture ”), among General Dynamics Corporation, a Delaware corporation (the “ Company ”), the Guarantors (as defined herein) and The Bank of New York Mellon, a New York banking corporation, as trustee (the “ Trustee ”) to the Indenture, dated as of August 27, 2001 (the “ Base Indenture ”), among the Company, the guarantors named therein and the Trustee.

WHEREAS, the Company, the Guarantors and the Trustee have heretofore executed and delivered the Base Indenture to provide for the issuance from time to time of Securities (as defined in the Base Indenture) of the Company, to be issued in one or more series;

WHEREAS, Section 9.01(5) of the Base Indenture provides, among other things, that the Company and the Trustee may enter into indentures supplemental to the Base Indenture for, among other things, the purpose of establishing the designation, form, terms and provisions of Securities of any series as provided by Articles 2 and 3 of the Base Indenture;

WHEREAS, the Company (i) desires the issuance of a new series of Securities to be designated as hereinafter provided and (ii) has requested the Trustee to enter into this Fifth Supplemental Indenture for the purpose of establishing the designation, form, terms and provisions of the Securities of such series;

WHEREAS, all action on the part of the Company necessary to authorize the issuance of said Securities under the Base Indenture and this Fifth Supplemental Indenture has been duly taken.

NOW, THEREFORE, THIS FIFTH SUPPLEMENTAL INDENTURE WITNESSETH:

That, in order to establish the designation, form, terms and provisions of, and to authorize the authentication and delivery of, said Securities, and in consideration of the acceptance of said Securities by the Holders thereof and of other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereto hereby agree as follows:

ARTICLE 1

D EFINITIONS

(a) Capitalized terms used herein and not otherwise defined herein shall have the respective meanings ascribed thereto in the Base Indenture.

(b) The rules of interpretation set forth in the Base Indenture shall be applied hereto as if set forth in full herein.

(c) For all purposes of this Fifth Supplemental Indenture, except as otherwise expressly provided or unless the context otherwise requires, the following terms shall have the following respective meanings (such meanings shall apply equally to both the singular and plural forms of the respective terms).

“ Comparable Treasury Issue ” means the United States Treasury security selected by an Independent Investment Banker as having a maturity comparable to the remaining term of the Notes to be redeemed that would be utilized, at the time of selection and in accordance with customary financial practice, in pricing new issues of corporate debt securities of comparable maturity to the remaining term of the Notes.

“ Comparable Treasury Price ” means, with respect to any Redemption Date for the Notes, the average of four Reference Treasury Dealer Quotations obtained by the Trustee for that applicable Redemption Date, after excluding the highest and lowest of such Reference Treasury Dealer Quotations, or, if the Trustee obtains fewer than four Reference Treasury Dealer Quotations, the average of all Reference Treasury Dealer Quotations obtained by the Trustee.

“ Guarantors ” means, initially, American Overseas Marine Corporation, a Delaware corporation, Bath Iron Works Corporation, a Maine corporation, Electric Boat Corporation, a Delaware corporation, General Dynamics Armament and Technical Products, Inc., a Delaware corporation, General Dynamics Government Systems Corporation, a Delaware corporation, General Dynamics Land Systems Inc., a Delaware corporation, General Dynamics Ordnance and Tactical Systems, Inc., a Virginia corporation, Gulfstream Aerospace Corporation, a Delaware corporation, and National Steel and Shipbuilding Company, a Nevada corporation.

“ Independent Investment Banker ” means one of the Reference Treasury Dealers, to be appointed by the Company.

“ Notes ” shall have the meaning ascribed thereto in Section 2.01(a) hereof.

“ Reference Treasury Dealer Quotations ” means, with respect to each Reference Treasury Dealer and any Redemption Date, the average, as determined by the Trustee, of the bid and asked prices for the Comparable Treasury Issue (expressed in each case as a percentage of its principal amount) quoted in writing to the Trustee by such Reference Treasury Dealer at 3:30 p.m., New York City time, on the third Business Day preceding the Redemption Date.

“ Reference Treasury Dealer ” means each of Banc of America Securities LLC, J.P. Morgan Securities Inc. and RBS Securities Inc. (so long as they continue to be primary U.S. Government securities dealers) and any one other primary U.S. Government securities dealer chosen by the Company, and their respective successors. If Banc of America Securities LLC, J.P. Morgan Securities Inc. or RBS Securities Inc. ceases to be a primary U.S. Government securities dealer, the Company will appoint in its place another nationally recognized investment banking firm that is a primary U.S. Government securities dealer.

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“ Remaining Scheduled Payments ” means, with respect to each Note that the Company is redeeming, the remaining scheduled payments of the principal thereof and interest thereon that would be due after the related Redemption Date if such Note were not redeemed. However, if the Redemption Date is not a scheduled interest payment date with respect to that Note, the amount of the next succeeding scheduled interest payment on that Note will be deemed to be reduced by the amount of interest accrued on such Note to the Redemption Date.

“ Treasury Rate ” means, with respect to any Redemption Date, the rate per annum equal to the semi-annual equivalent yield to maturity of the Comparable Treasury Issue, calculated using a price for the Comparable Treasury Issue (expressed as a percentage of its principal amount) equal to the Comparable Treasury Price for that Redemption Date. The Treasury Rate will be calculated on and as of the third Business Day immediately preceding the Redemption Date.

ARTICLE 2

G ENERAL T ERMS AND C ONDITIONS OF THE N OTES

Section 2.01 . Designation and Principal Amount.

(a) There is hereby authorized a new series of Securities designated the 1.800% Notes due 2011 (the “ Notes ”).

(b) The aggregate principal amount of the Notes authorized by this Fifth Supplemental Indenture shall initially be $750,000,000.

(c) The Notes may be issued from time to time upon written order of the Company to the Trustee for the authentication and delivery of the Notes pursuant to Section 3.03 of the Base Indenture.

(d) The Notes shall have and be subject to such other terms as provided in the Base Indenture and shall be evidenced by one or more Securities of that series in the form of Section 4.01.

(e) The Notes shall be issuable in denominations of $2,000 and integral multiples of $1,000 above that amount.

Section 2.02 . Maturity.

(a) The date upon which the Notes shall become due and payable at final maturity, together with any accrued and unpaid interest, is July 15, 2011 (the “ Maturity Date ”).

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Section 2.03 . Interest.

(a) The Notes will bear interest at the rate of 1.800% per annum (the “ Interest Rate ”) from June 24, 2009, until the principal thereof becomes due and payable. Interest on the Notes will be payable semi-annually in arrears on the Interest Payment Dates (as defined in the Base Indenture) with respect to the Notes, which shall be January 15 and July 15 of each year, commencing January 15, 2010, to the Person in whose name any such Note or any predecessor Note is registered, at the close of business on the Regular Record Date with respect to the Notes for such interest installment, which, in the case of a Global Security, shall be the close of business on the January 1 and July 1 next preceding such Interest Payment Date. If the Notes are no longer in book-entry only form, the Regular Record Dates for the Notes shall also be the close of business on the January 1 and July 1 next preceding such Interest Payment Date.

(b) In the event that any Interest Payment Date with respect to the Notes is not a Business Day, then payment of interest payable on such date will be made on the next succeeding day which is a Business Day, with the same force and effect as if made on such date, and no interest shall accrue on the amount so payable from the period from and after such interest Payment Date.

Section 2.04 . Global Securities.

The Notes shall be issued in the form of one or more Global Securities in an aggregate principal amount equal to the aggregate principal amount of all outstanding Notes of that series, to be registered in the name of the Depository, or its nominee, and delivered by the Trustee to or upon the order of the Depository for crediting to the accounts of its participants pursuant to the written instructions of the Company. The Company upon any such presentation shall execute one or more Global Securities in such aggregate principal amount and deliver the same to the Trustee for authentication and delivery in accordance with the Base Indenture and this Fifth Supplemental Indenture. Payments on Notes issued as one or more Global Securities will be made to the Depository.

ARTICLE 3

R EDEMPTION OF THE N OTES

Section 3.01 . Optional Redemption of the Notes.

(a) The Company may, at its option, at any time and from time to time, redeem the Notes issued under this Fifth Supplemental Indenture, in whole or in part, upon payment of a redemption price equal to (A) the greater of (i) 100% of the principal amount of the Notes to be redeemed or (ii) the sum of the present values of the Remaining Scheduled Payments discounted to the Redemption Date on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months), at the Treasury Rate plus 12.5 basis points, plus (B) accrued and unpaid interest, if any, on the principal amount of Notes being redeemed to but excluding the Redemption Date (the “ Redemption Price ”).

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(b) With respect to the Notes, all references to Redemption Price in the Base Indenture shall mean Redemption Price as defined in this Fifth Supplemental Indenture.

Section 3.02 . No Sinking Fund.

The Notes are not entitled to the benefit of any sinking fund.

ARTICLE 4

F ORM OF N OTES

Section 4.01 . Form of Note.

[TO BE INSERTED ON GLOBAL SECURITIES]

UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, TO THE COMPANY OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IN EXCHANGE FOR THIS CERTIFICATE OR ANY PORTION HEREOF IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY OR SUCH OTHER REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY OR SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY (AND ANY PAYMENT HEREON IS MADE TO CEDE & CO.), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON OTHER THAN THE DEPOSITORY TRUST COMPANY OR CEDE & CO. IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

THIS SECURITY IS A GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF A DEPOSITORY OR A NOMINEE THEREOF. TRANSFERS OF THIS GLOBAL SECURITY SHALL BE LIMITED TO TRANSFERS IN WHOLE, BUT NOT IN PART, TO NOMINEES OF THE DEPOSITORY TRUST COMPANY OR TO A SUCCESSOR THEREOF OR SUCH SUCCESSOR’S NOMINEE AND TRANSFERS OF PORTIONS OF THIS GLOBAL SECURITY SHALL BE LIMITED TO TRANSFERS MADE IN ACCORDANCE WITH THE RESTRICTIONS SET FORTH IN THE INDENTURE REFERRED TO ON THE REVERSE HEREOF.

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$[                                         ]

GENERAL DYNAMICS CORPORATION

1.800% Notes Due 2011

GENERAL DYNAMICS CORPORATION, a corporation duly organized and existing under the laws of Delaware (herein called the “ Company, ” which term includes any successor corporation under the Indenture referred to on the reverse hereof), for value received, hereby promises to pay to [    ] or its registered assigns, the principal sum of [    ] $ [    ] on July 15, 2011, and to pay interest thereon from and including June 24, 2009 or from and including the most recent Interest Payment Date (as hereinafter defined) to which interest has been paid or duly provided for, as the case may be.

Interest will be paid semi-annually on January 15 and July 15 of each year (each, an “ Interest Payment Date ”), commencing January 15, 2010, at the rate of 1.800% per annum, until the principal hereof is paid or made available for payment. The interest so payable and punctually paid or duly provided for on any Interest Payment Date will, as provided in the Indenture, be paid to the Person in whose name this Note (or one or more predecessor Notes) is registered at the close of business on the Regular Record Date for such interest, which shall be the January 1 and July 1, as the case may be, immediately preceding such Interest Payment Date. Except as otherwise provided in the Indenture, any such interest not so punctually paid or duly provided for will forthwith cease to be payable to the Holder on such Regular Record Date and may either be paid (i) to the Person in whose name this Note (or one or more predecessor Notes) is registered at the close of business on a Special Record Date for the payment of such Defaulted Interest to be fixed by the Trustee, notice whereof is to be given to Holders of Notes not less than 10 calendar days prior to such Special Record Date, or (ii) in any other lawful manner