Patent ID: 6186447
Filing Date: 2001-02-13
Classification: B64D,F02C

Abstract:
In an autothrottle control system having the capability to reduce engine throttle setting from a first position to an idle position during landing by use of a nominal retard rate signal calculated as the angular difference between a current engine throttle control lever position and an idle engine throttle control lever position, the difference being divided by an amount of time to touchdown, an improvement comprising:calculating a retard rate adjustment signal as a function of the difference between current airspeed and a commanded airspeed, the retard rate adjustment signal being expressed as an angular amount per time;combining the nominal retard rate signal with the retard rate adjustment signal to form a retard rate output signal; andusing the retard rate output signal to control the movement of engine throttles to idle;wherein the retard rate adjustment signal decreases the rate of throttle reduction during underspeed conditions and increases the rate of throttle reduction during overspeed conditions thereby helping to avoid hard and soft landings, respectively.