Monitoring airplane takeoff performance - Prototype instrument with learning capability

Abstract

An instrument has been developed that gives easily interpreted real-time quantification of aircraft groundroll takeoff performance. The instrument has the capability of evaluating and remembering (i.e., learning) nominal takeoff performance and does not depend on Pilot Operating Handbook values. The analytical model used to predict the expected aircraft acceleration and distances uses input values for field elevation; pressure; temperature; runway direction, slope, and friction condition; wind direction and magnitude; aircraft gross weight; reference airspeed; and power or thrust setting. The instrument requires no interface with aircraft systems except electric power. The actual parameter that is measured is the longitudinal axis acceleration. The real-time takeoff performance quantification is displayed to the pilot in two forms: 1) an acceleration ratio displayed on a screen as a continuous time-line function and 2) a digital display of pertinent ground-roll distances. These displays would appear in a panel instrument similar in size to current stormscopes and/or incorporated in a heads-up display. The takeoff performance is available to the crew as soon as the takeoff power is set. By utilizing this information the pilot is aided in making critical NO-GO decisions early in the takeoff roll when a rejected takeoff can be safely accomplished from low speed.