Patent ID: 6761336
Filing Date: 2004-07-13
Classification: B64D,G05D

Abstract:
In an aircraft flight control system having a normal pitch command signal provided to a pitch control device for altering the aircraft's pitch attitude, an improvement for reducing the likelihood of an aircraft tailstrike, the improvement comprising:(a) determining a current tailskid height and a current tailskid closure rate wherein the current tailskid closure rate is determined at least in part by vertical speed of at least a part of the aircraft; (b) comparing the current tailskid closure rate with a threshold closure rate to determine an excess closure rate amount, the threshold closure rate being dependent upon the current tailskid height; and (c) adding an incremental nose-down pitch command signal to the normal pitch command signal to avoid a potential aircraft tailstrike, the incremental nose-down pitch command signal being calculated as a function of the excess closure rate amount.