U.S. Code > Title 10 Armed Forces > Subtitle A—General Military Law (§§ 101—2925) > PART II—PERSONNEL (§§ 501—1801_to_1805) > CHAPTER 36—PROMOTION, SEPARATION, AND INVOLUNTARY RETIREMENT OF OFFICERS ON THE ACTIVE-DUTY LIST (§§ 611—647) > SUBCHAPTER III—FAILURE OF SELECTION FOR PROMOTION AND RETIREMENT FOR YEARS OF SERVICE (§§ 627—636) > § 633. Retirement for years of service: regular lieutenant colonels and commanders

§ 633. Retirement for years of service: regular lieutenant colonels and commanders

(a) 28 Years of Active Commissioned Service.— Except as provided in subsection (b) and as provided under section 637 (b) of this title, each officer of the Regular Army, Regular Air Force, or Regular Marine Corps who holds the regular grade of lieutenant colonel, and each officer of the Regular Navy who holds the regular grade of commander, who is not on a list of officers recommended for promotion to the regular grade of colonel or captain, respectively, shall, if not earlier retired, be retired on the first day of the month after the month in which he completes 28 years of active commissioned service.
(b) Exceptions.— Subsection (a) does not apply to the following:
(1) An officer of the Navy or Marine Corps who is an officer designated for limited duty to whom section 5596 (e) or 6383 of this title applies.
(2) An officer of the Navy or Marine Corps who is a permanent professor at the United States Naval Academy.