The first X-31 (Bu. No. 164584) flies over Edwards Air Force Base, California, in 1993. Aircraft 584 completed 292 flights during the Enhanced Fighter Maneuverability (EFM) program before being lost on January 19, 1995 when icing in the nose probe caused the flight control computer to receive bad data. German test pilot Karl-Heinz Lang ejected after the aircraft became uncontrollable. The program continued, using the second aircraft (Bu. No. 164585).