Adaptive Engine Control System

The Adaptive Engine Control System (ADECS) improved engine perfor­mance by exploiting the excess stall margin originally designed into the engines using capabilities made possible with the integrated comput­erized flight and engine control systems.[1263] ADECS used airframe and engine data to allow the engine to operate at higher performance levels at times when inlet distortion was low and the full engine stall margin is not needed. Initial engineering work on ADECS began in 1983, with research flights beginning in 1986. Test results showed thrust improve­ments of between 8 and 10 percent depending on altitude. Fuel flow reductions of between 7 and 17 percent at maximum afterburning thrust at an altitude of 30,000 feet were recorded. Rate of climb increased 14 percent at 40,000 feet. Time required to climb from 10,000 feet to 40,000 feet dropped 13 percent. Acceleration improved between 5 and 24 per­cent at intermediate and maximum power settings, depending on altitude. No unintentional engine stalls were encountered in the test program.

ADECS technology has been incorporated into the Pratt & Whitney F119 engine used on the Air Force F-22 Raptor.[1264]