§ 630. Discharge of commissioned officers with less then six years of active commissioned service or found not qualified for promotion for first lieutenant or lieutenant (junior grade)
The Secretary of the military department concerned, under regulations prescribed by the Secretary of Defense—
(2)
shall, unless the officer has been promoted, discharge any officer described in paragraph (1)(B) at the end of the 18-month period beginning on the date on which the officer is first found not qualified for promotion.