21st Congress of International Council of the Aeronautical Sciences, Melbourne, Australia, 13-18 September, 1998
Paper ICAS-98-5.5.2

MECHANICAL FAILURES OF FLAP CONTROL SYSTEMS AND RELATED MONITORING TECHNIQUES

Borello L., Villero G.
Turin Polytechnical University, Italy

Keywords: mechanical failures, flap control systems, monitoring techniques

This work analyses some monitoring techniques related to different troubles affecting flap control systems in order to compare the dynamic behaviour of a typical irreversible actuator architecture system and a typical reversible actuator (with wingtip brakes) architecture system under the main mechanical and supply pressure failures. The monitoring mathematical models and the related simulation computer program of a typical control system under the above mentioned failures have been prepared. This computer simulation program further analyses the flight control dynamic behaviour and the airplane 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 different monitoring strategies in failure conditions. Some simulations of the control system and airplane behaviour with the above mentioned failures have been performed. 'The results of the present work show the high sensitivity of the aircraft controllability to the monitoring technique used to detect flaps asymmetries and the prevention of major troubles related to the wingtip brakes failure, to the irreversibility failure following structural vibrations and to the supply pressure drop.

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