Exhibit 3.1

THIRD AMENDED AND RESTATED

CERTIFICATE OF INCORPORATION OF

PAE INCORPORATED

Article I

The name of the corporation is PAE INCORPORATED (the “Corporation”).

Article II

The address of the Corporation’s registered office in the State of Delaware is 1209 Orange Street, City of Wilmington, County of New Castle, Delaware 19801. The name of its registered agent at such address is The Corporation Trust Company.

Article III

The purpose of the Corporation is to engage in any lawful act or activity for which corporations may be organized under the General Corporation Law of the State of Delaware, as the same exists or as may hereafter be amended (the “DGCL”).

Article IV

The Corporation shall have the authority to issue one thousand (1,000) shares of capital stock, all of which shall be shares of common stock, par value $0.0001 per share.

Article V

The Corporation is to have perpetual existence.

Article VI

The business and affairs of the Corporation shall be managed by or under the direction of a board of directors. The authorized number of directors shall be determined from time to time by a resolution adopted by affirmative vote of a majority of the entire board of directors. In furtherance and not in limitation of the powers conferred by statute, the board of directors is expressly authorized to adopt, amend or repeal the bylaws of the Corporation.

Article VII

Meetings of stockholders may be held within or without the State of Delaware, as the bylaws of the Corporation may provide. The books of the Corporation may be kept outside the State of Delaware at such place or places as may be designated from time to time by the board of directors or in the bylaws of the Corporation. Election of directors need not be by written ballot unless the bylaws of the Corporation so provide.

Article VIII

A director of the Corporation shall not be personally liable to the Corporation or its stockholders for monetary damages for breach of fiduciary duty as a director, except to the extent such exemption from liability or limitation thereof is not permitted under the DGCL as the same exists or may hereafter be amended. Any amendment, modification or repeal of the foregoing sentence shall not adversely affect any right or protection of a director of the Corporation hereunder in respect of any act or omission occurring prior to the time of such amendment, modification or repeal.

To the fullest extent permitted by Delaware law, as the same exists or may hereafter be amended, the Corporation shall indemnify and hold harmless each person who is or was made a party or is threatened to be made a party to or is otherwise involved in any threatened, pending or completed action, suit or proceeding, whether civil, criminal, administrative or investigative, including an action by or in the right of the Corporation to procure a judgment in its favor (each, a “proceeding”), by reason of the fact that he or she is or was a director, officer, employee or agent of the Corporation or, while a director, officer, employee or agent of the Corporation, is or was serving at the request of the Corporation as a director, officer, employee or agent of another corporation or of a partnership, joint venture, trust, other enterprise or nonprofit entity, including service with respect to an employee benefit plan (an “indemnitee”), whether the basis of such proceeding is alleged action in an official capacity as a director, officer, employee or agent, or in any other capacity while serving as a director, officer, employee or agent, against all liability and loss suffered and expenses (including, without limitation, attorneys’ fees and disbursements, judgments, fines, excise taxes under the Employee Retirement Income Security Act of 1974, damages, claims and penalties and amounts paid in settlement) reasonably incurred by such indemnitee in connection with such proceeding. The Corporation shall to the fullest extent not prohibited by applicable law pay the expenses (including attorneys’ fees) incurred by an indemnitee in defending or otherwise participating in any proceeding in advance of its final disposition; provided, however, that, to the extent required by applicable law, such payment of expenses in advance of the final disposition of the proceeding shall be made only upon receipt of an undertaking, by or on behalf of the indemnitee, to repay all amounts so advanced if it shall ultimately be determined that the indemnitee is not entitled to be indemnified under this Article VIII or otherwise. The rights to indemnification and advancement of expenses conferred by this Article VIII shall be contract rights and such rights shall continue as to an indemnitee who has ceased to be a director, officer, employee or agent and shall inure to the benefit of his or her heirs, executors and administrators. Notwithstanding the foregoing provisions of this paragraph, except for proceedings to enforce rights to indemnification and advancement of expenses, the Corporation shall indemnify and advance expenses to an indemnitee in connection with a proceeding (or part thereof) initiated by such indemnitee only if such proceeding (or part thereof) was authorized by the board of directors.

The rights to indemnification and advancement of expenses conferred on any indemnitee by this Article VIII shall not be exclusive of any other rights that any indemnitee may have or hereafter acquire under law, this certificate of incorporation, the bylaws of the Corporation, an agreement, vote of stockholders or disinterested directors, or otherwise.

Any repeal or amendment of this Article VIII by the stockholders of the Corporation or by changes in law, or the adoption of any other provision of this certificate of incorporation inconsistent with this Article VIII, shall, unless otherwise required by law, be prospective only (except to the extent such amendment or change in law permits the Corporation to provide broader indemnification rights on a retroactive basis than permitted prior thereto), and shall not in any way diminish or adversely affect any right or protection existing at the time of such repeal or amendment or adoption of such inconsistent provision in respect of any proceeding (regardless of when such proceeding is first threatened, commenced or completed) arising out of, or related to, any act or omission occurring prior to such repeal or amendment or adoption of such inconsistent provision.

This Article VIII shall not limit the right of the Corporation, to the extent and in the manner authorized or permitted by law, to indemnify and to advance expenses to persons other than indemnitees.

Article IX

The Corporation expressly elects not to be governed by Section 203 of the DGCL.

Article X

The Corporation reserves the right to amend, alter, change or repeal any provision contained in this certificate of incorporation in the manner now or hereafter prescribed herein and by the laws of the State of Delaware, and all rights conferred upon stockholders herein are granted subject to this reservation.