Envelope-aware flight management for loss of control prevention given rudder jam

Abstract

The Envelope-Aware Flight Management System is an augmentation to a conventional flight management system that prevents or recovers from loss of control. Loss of control is defined in this work as an excursion outside the admissible flight envelope. The Envelope-Aware Flight Management System combines flight safety assessment and management, envelope estimation, flight planning, system identification, and adaptive control functions. This paper describes integration of envelope estimation, flight planning, and flight safety assessment and management to identify situations of high loss-of-control risk, override the nominal crew/flight-management-systemjust in time to prevent loss of control, and safely recover the aircraft. The Envelope-Aware Flight Management System is applied to prevent inflight loss of control for a Twin Otter experiencing a rudder jam, a failure that can be identified and modeled a priori. Recovery translates to identifying and maintaining states within the contracted flight envelope, as well as building and following an emergency landing plan that respects the new envelope.