Operated by 457 AS. Later to the US Army as 84-00158 and converted to a C-12U-3.

Only just withdrawn from use when it was pictured at a platform at Edwards (the fin tip of the aircraft was temporarly cannibalized to keep another prototype in the air), this B-1A prototype in a great camouflage jacket. The 74-0158 made its first flight on 23 December 1974 as the first of four prototypes of the Lancer from Air Force Plant 42, Palmdale (CA). By the time that the B-1A programme was cancelled, 0158 had made 79 flights totaling 405,3 hours. It was eventually dismantled and used for weapons training at Lowry Air Force Base, Colorado.