Mechanical failures of flap control systems: proposal of advanced monitoring techniques

This work proposes and analyses some asymmetry monitoring techniques for flap and slat control systems equipped with reversible actuators in order to compare their performances in the event of a transmission line failure. The monitoring mathematical models and the related simulation computer program of a typical control system under a transmission failure have been prepared. This computer simulation program furtherly analyses the flight control dynamic behaviour and the aeroplane lateral-directional behaviour under the action of the primary and secondary flight controls and of the autopilot. The purpose of this paper is to evaluate the effects of the different proposed monitoring strategies on the maximum asymmetry in failure conditions. Some simulations of the control system and aeroplane behaviour with the above mentioned failures have been performed. The conclusions remark the high sensitivity of the failure behaviour of the secondary flight control systems (either in transient or in steady condition) and of the aeroplane to the employed monitoring model.