10 U.S.C. § 9540

(a) Whenever he considers that it is advantageous to the national defense and that existing facilities of the Department of the Air Force are inadequate, the Secretary of the Air Force may, by contract or otherwise, employ the architectural or engineering services of any person outside that Department for producing and delivering designs, plans, drawings, and specifications needed for any public works or utilities project of the Department. (b) The fee for any service under this section may not be more than 10 percent of the estimated cost, as determined by the Secretary, of the project to which it applies. (c) Sections 305, 3324, and 7204, chapter 51, and subchapters III, IV, and VI of chapter 53 of title 5 do not apply to employment under this section.