Flight Safety Assessment and Management for Takeoff Using Deterministic Moore Machines

Abstract

This paper presents a novel flight safety assessment and management augmentation to the flight management system designed to assist a flight crew in avoiding or recovering from impending loss-of-control situations. Nominally, this system serves as a passive monitor but, in high-risk situations, warnings and (ultimately) override actions are initiated to mitigate the high-risk situation. In this work, flight safety assessment and management is applied to the task of preserving safety during takeoff, which is one of the highest-risk phases of flight. Flight safety assessment and management is specified as a deterministic Moore machine that can ultimately be certified using existing software certification processes. To facilitate understanding and to reduce state-space complexity, flight safety assessment and management’s state machines are split into longitudinal and lateral-directional submachines that identify and mitigate loss-of-control contributing factors associated with aircraft dynamics and control constraints. Case studies based on documented takeoff accidents are presented to evaluate flight safety assessment and management’s ability to maintain safe flight in realistic loss-of-control scenarios. Results from these case studies illustrate that flight safety assessment and management could have averted the takeoff accidents that were considered. A discussion of other factors that must be considered before realizing a comprehensive flight safety assessment and management capability for takeoff is provided.