Jet-A before being introduced into the engine for burning. This restoration is called degradation and was accomplished on the Boeing 720 using a device called a degrader. Each of the four Pratt & Whitney JT3C-7 engines had a degrader built and installed by General Electric (GE) to break down and return the AMK to near Jet-A quality. In addition to the AMK research, NASA Langley Research Center was involved in a structural load measurement experiment, which included using instrumented crash dummies in the seats of the passenger compartment and cockpit. Before the final flight in 1984, more than four years of effort was expended in attempting to establish final impact conditions which would be considered to be survivable by the FAA. Over a series of 14 flights, General Electric installed and tested four degraders (one on each engine); the FAA refined AMK, blending, testing, and fueling a full size aircraft. During the flights the aircraft made approximately 69 approaches, to about above the prepared crash site, under remote control. These flights were used to introduce AMK one step at a time into some of the fuel tanks and engines while monitoring the performance of the engines. During those same flights, NASA's Dryden Flight Research Center also developed the remote piloting techniques necessary for the Boeing 720 to fly as a drone aircraft. An initial attempt at the full-scale test was scrubbed in late 1983 due to problems with the uplink connection to the 720; if the uplink failed the ground-based pilot would no longer have control of the aircraft. Test execution On the morning of December 1, 1984, the test aircraft took off from Edwards Air Force Base, California, made a left-hand departure and climbed to an altitude of . The aircraft was remotely flown by NASA research pilot Fitzhugh Fulton from the NASA Dryden Remotely Controlled Vehicle Facility. All fuel tanks were filled with a total of of AMK and all engines ran from start-up to impact (flight time was 9 minutes) on the modified Jet-A. It then began a descent-to-landing along the roughly 3.8-degree glideslope to a specially prepared runway on the east side of Rogers Dry Lake, with the landing gear remaining retracted. Passing the decision height of above ground level (AGL), the aircraft turned slightly to the right of the desired path. The aircraft entered into a situation known as a Dutch roll. Slightly above that