Aircraft tailstrike avoidance system

The invention relates to a method for reducing the likelihood of an aircraft tail strike in an aircraft flight control system (16) having a normal pitch command signal provided to a pitch control device (18) for altering the aircraft's pitch attitude, the method comprising: (a) determining a current pitch angle margin and a current pitch rate; (b) comparing the current pitch rate with a threshold pitch rate to determine an excess pitch rate amount, the threshold pitch rate being dependent upon the current pitch angle margin, and comparing the current pitch angle margin with a threshold pitch angle margin (104,122) to determine a excess pitch angle margin amount, the threshold pitch angle margin being dependent upon the current pitch rate; (c) adding an incremental nose-down pitch command signal to the normal pitch command signal to avoid a potential aircraft tail strike, the incremental nose-down pitch command signal being calculated as a function of the excess pitch rate amount or of the excess pitch angle margin amount.