Development of a generic test for transient recovery handling from helicopter active inceptor system failures to a near-zero control force condition

Abstract

In the event of an aircraft’s cyclic Active Inceptor System(AIS) failure, causing sudden loss of actively generated control forces, its flight control mechanical characteristics (FCMC) would degrade to the system’s inherent, nearzero force characteristics (the isotonic mode). In this degraded mode the pilot would have to recover the control of the aircraft and then land the aircraft safely. In order to mitigate the risks associated with this failure and to optimise the inherent FCMC and augmentation laws for improved handling qualities (HQ), a standardised and generic test that incorporated all influencing worst case flight and control parameters needed to be defined. The data from simulator evaluations were analysed and it was concluded that the most influencing parameters on the severity of transient response and recovery were the steady inceptor force and the pilot's level of attentiveness at the point of failure. Using the results of this analysis, a generic test is presented for isotonic AIS failure mode evaluation.