An F-15A used by NASA's Dryden Flight Research Facility, Edwards, California, for digital electronic flight and engine control systems development carries NASA aircraft number 835 (USAF Serial #71-0287). The aircraft, obtained by NASA in 1976, was used to develop the digital electronic engine control (DEEC) system now used on many current fighter aircraft. Research programs flown on the testbed aircraft have demonstrated improved rates of climb, fuel savings, and engine thrust by optimizing systems performance. The aircraft, later called the F-15 HIDEC (Highly Integrated Digital Electronic Control) Flight Facility, also tested and evaluated a computerized self-repairing flight control system for the Air Force that detects damaged or failed flight control surfaces. The system then reconfigures undamaged control surfaces so the mission can continue and the aircraft is landed safely.