AIRCRAFT PERFORMANCE MARGIN INDICATOR

An aircraft performance margin indicator including a display (21) that, during takeoff and landing, informs the pilot of the ability of the aircraft to either stop safely or achieve a safe flying speed before reaching the end of the runway is disclosed. A plurality of dedicated microprocessors (41, 43, 45, and 47), each of which receives pertinent data about the aircraft, the runway and the existing environmental conditions, produce one or more symbol control signals. The symbol control signals control the position of symbols that form part of the display (21). The display scale is a normalized runway and the display includes an airplane symbol (23) that shows the location of the aircraft as the aircraft moves down the runway. The microprocessor controlled symbols include GO and STOP bugs ' (25 and 31) and a ROTATE bar (27). The ROTATE bar indicates the last point at which the aircraft can be safely rotated under present FFA regulations. The position of the GO bug (25) indicates the last point at which the application of maximum thrust will result in the aircraft reaching rotation speed (at the ROTATE bar position) and achieve a safe takeoff. The position of the STOP bug indicates the last point at which the application of maximum braking will result in the aircraft stopping before reaching the end of the runway. As long as the bugs remain in front of the airplane symbol, the denoted option (go or stop) remains available. Once the airplane symbol passes a bug, the denoted option is no longer available. Preferably, the microprocessor controlled symbols also include: an engine-out (EO) bug (29) that indicates the last point at which the application of maximum thrust will allow the aircraft to sefely takeoff with an inoperative engine; and, a VMC bar (33) indicating the distance needed to stop at the time the aircraft achieves minimum control speed.