Three U.S. Air Force General Dynamics F-111As of the 428th Tactical Fighter Squadron returning from a "Combat Lancer" mission in 1968. The first production F-111A deliveries to the USAF took place on 18 July 1967 to the 428th, 492nd and 430th Tactical Fighter Squadrons of the 474th Tactical Fighter Wing based at Cannon AFB, New Mexico (USA). In early 1968, the wing was reassigned to Nellis AFB, Nevada.
Shortly thereafter, the USAF decided to rush a small detachment of F-111As to Southeast Asia under a program known as "Combat Lancer". Six 428th TFS F-111As were allocated to the "Combat Lancer" program, and departed Nellis AFB for Takhli RTAFB on 15 March 1968. By the end of that month, 55 night missions had been flown against targets in North Vietnam, but two aircraft had been lost. 66-0022 had been lost on 28 March, and 66-0017 on 30 March. Replacement aircraft had left Nellis, but the loss of a third F-111A (66-0024) on 22 April halted F-111A combat operations until 1972.