527 §8540. Educational institutions: detail of members of regular or reserve components as professors and instructors in air science and tactics (a) The President may detail regular or reserve members of the Air Force for duty as professors and assistant professors of air science and tactics, and as military instructors, at educational institutions where units of the Air Keserve Officers' Training Corps are maintained. (b) The Secretary of the Air Force may detail regular or reserve meml3ers of the Air Force for duty as professors and assistant professors of air science and tactics, and as military instructors, at schools and colleges, other than those covered by section 9382 of this title, having a course of military training prescribed by him and having not less than 100 physical fit male students who are at least 14 years of age. § 8541. National Guard Bureau: assignment of officers of regular or reserve components Except as provided in section 8496(b) of this title, the President may assign to duty in the National Guard Bureau as many regular or reserve officers of the Air Force as he considers necessary. § 8542. Chief and assistant chief of staflf of wings of Air National Guard in Federal service: detail The President may detail a regular or reserve officer of the Air Force as chief of staff, and a regular or reserve officer or an officer of the Air National Guard as assistant to the chief of staff, of any wing of the Air National Guard that is in Federal service as an Air National Guard organization. § 8543. Aides: detail; number authorized (a) Each major general of the Air Force is entitled to three aides selected by him from commissioned officers of the Air Force in any grade below major. (b) Each brigadier general of the Air Force is entitled to two aides selected by him from commissioned officers of the Air Force in any grade below captain. §8544. Duties: regular officers; performance of civil functions restricted (a) No commissioned officer of the Regular Air Force may be— (1) employed on civil works or internal improvements; (2) allowed to be employed by an incorporated company; or (3) employed as acting paymaster or disbursing agent of the Bureau of Indian Affairs: if that employment requires him to be separated from his unit or organization, or interferes with the performance of his military duties. (b) Except as otherwise provided by law, no commissioned officer on the active list of the Regular Air Force may hold a civil office by election or appointment, whether under the United States, a Territory or possession, or a State. The acceptance of such a civil office or the exercise of its functions by such an officer terminates his appointment in the Air Force.