ABSTRACT
The goal of the enhanced fighter maneuverability (EFM) program is to demonstrate the tactical advantage of a fighter aircraft being capable of maneuvering and maintaining controlled flight including the post-stall regime up to 70° AoA. The safety-critical flight control components are electrically quadruplex and connected to all flight control computers (FCCs). The X-31A flight control system is a full-authority digital fly-by-wire system. It consists of identical FCCs supported by a so-called tie-breaker FCC. The X-31A post-stall experimental aircraft was developed to demonstrate EFM by using thrust vectoring to fly beyond the stall limit. An extensive tactical flight test to demonstrate the EFM capability of the X-31A aircraft was performed at Dryden Flight Research Center in 1994 after the operational post-stall (PST) clearance was given. The X-31A aircraft is a longitudinal unstable delta-wing A/C with canard configuration. PST flight is only possible if the aircraft is in the AoA command mode.
