Aircraft control system

A system (10) aircraft control having: means (12) for detecting an irregularity in aircraft handling during flight; means (18) responsive to an output of the means (12) to cause detection rigid body excitation in at least one of the plane; means (20) for controlling a real excitation of rigid body response; means (22) for a comparison of the actual response with a target response of the aircraft to the rigid body excitation; and means (24) responsive to an output of the comparison means to determine the need for a modification of the current flight plan for dealing with the irregularity and for generating a corresponding control output.