first missile was now linked to perception of the aircraft. In April 1972, the Senate published its report on CAS. The report recommended funding of the Air Force's A-X program, which would become the A-10 Thunderbolt II and limited procurement of the Harrier for the Marine Corps. The report never referred to the Cheyenne by name and only offered a lukewarm recommendation for the Army to continue procurement of attack helicopters, so long as their survivability could be improved. The Cheyenne program was canceled by the Secretary of the Army on 9 August 1972. The helicopter's large size and inadequate night/all-weather capability were reasons stated by the Army for the cancellation. The Cheyenne's analog and mechanical weapons systems were becoming out of date as new digital systems that were more accurate, faster, and lighter were being developed. The Cheyenne's unit cost had increased and was likely to increase further if new avionics were incorporated. On 17 August 1972, the Army initiated the Advanced Attack Helicopter (AAH) program. AAH sought an attack helicopter based on combat experience in Vietnam, with a lower top speed of 145 kn (167 mph, 269 km/h) and twin engines for improved survivability. Lockheed offered the CL-1700, a modified version of the Cheyenne with two engines and omitted the pusher propeller, without success. The AAH program led to the AH-64 Apache, which entered service in the mid-1980s. After the cancellation, the Army conducted an evaluation of the seventh Cheyenne equipped with the AMCS flight control system. The testing showed the AMCS removed most of the remaining control problems, improved stability, improved handling, and decreased the pilot workload. With the AMCS, the Cheyenne reached a speed of 215 kn (247 mph, 398 km/h) in level flight and in a dive achieved 245 kn (282 mph, 454 km/h); it also demonstrated improved maneuverability at high speeds. Prototype #7 was the last Cheyenne to fly. Lockheed had counted on the Cheyenne to establish itself in the helicopter market with its rigid rotor technology, but the ambitious project was unsuccessful. The firm did not pursue development of another helicopter. Lockheed proposed a civilian version of the Cheyenne as the CL-1026. This would have been a 30-seater helicopter, but the design never made it off the drawing board. Surviving aircraft No. 2 66-8827 is on display at Fort Polk, Louisiana. No. 5 66-8830 is stored at the Army Aviation Museum, Fort Rucker,