10/31/2007. Remarks by Johan Visschedijk: "Built for the AMST program, this was the first of two YC-15A prototypes and was first flown Long Beach, California, USA on August 26, 1975, with YC-15 Project pilot Kenneth Lewis and USAF Major John Harris at the controls. The second prototype, s/n 72-1876, was flown on December 5, 1975.

Late 1976 the first prototype was refurbished with a new longer wing and the No. 1 Pratt & Whitney JT8D-17 turbofan engine of 16,000 lb (7,257 kg) st was replaced by a 22,000 lb (9,979 kg) st CFM56-2 turbofan and was flown for the first time on February 16, 1977. After cancellation of the AMST program in 1979, the YC-14A prototypes were placed in storage at AMARC, the first eventual being displayed at Pima Air and Space Museum, Tucson, Arizona."