A little history on this aircraft.
Two ...... were built, one with a wingspan of 110 feet (#72-1876) and one with 132 feet (#72-1875). Both were 124 feet (38 m) long and powered by four Pratt Whitney JT8D-17 engines, each with 15,500 lbf (68.9 kN) of thrust.
The first flight was August 26, 1975. The second prototype followed in December. They were tested for some time at McDonnell Douglas as the Boeing entry was not ready until almost a year later. In November 1976 both designs were transferred to Edwards Air Force Base for head-to-head testing, including lifting heavy loads like tanks and artillery from dirt airfields at Graham Ranch, off the end of Runway 22.
The ...... completed a 600 hour flight test program in 1977. By this point the seeds of the AMST program's demise had already been sown. In March 1976 the Air Force Chief of Staff Gen. David C. Jones asked the Air Force Systems Command to see if it was possible to use a single model of the AMST for both strategic and tactical airlift roles, or alternately, if it was possible to develop non-STOL derivatives of the AMST for the strategic airlift role. This led to a series of studies which basically stated that such a modification was not easy, and would require major changes to either design to produce a much larger aircraft.
Although the ...... and ....... both met or exceeded the specifications of the contest, the increasing importance of the strategic vs. tactical mission eventually led the Air Force to conclude that they were better off with an updated C-130 in the short term. The AMST program was canceled in 1979. In January 1979, the C-X Task Force formed to develop the required strategic aircraft. The C-X eventually became the C-17 Globemaster III, developed on the basis of the .......
After the flight test program, the two aircraft were stored at the AMARC, located at Davis-Monthan Air Force Base. One was subsequently displayed at the nearby Pima Air Space Museum.AMARC's ....., 72-1875 (the first one built), was later returned to flying status by McDonnell Douglas in 1996, and resumed flying in April 1997. The intention was to use the .....to evaluate new technology for advanced tactical transports. After an engine failed, the aircraft was deemed too expensive to repair and was returned to storage, sitting for a number of years at the Boeing facility at Air Force Plant 42, in Palmdale, California, before being moved to back to Edwards, where it is now on display at the Air Force Flight Test Center Museum's "Century Circle" display area, just outside the base's west gate.
Info from Wikipedia