Aircraft Mode and Energy-State Prediction, Assessment, and Alerting

Abstract

This paper describes the implementation and evaluation of technologies that predict and assess the future aircraft energy state and autoflight configuration and provide appropriate alerting to better inform pilots of the effect of problematic autoflight inputs or conditions. Prediction algorithms are used to extrapolate the current state of the aircraft based on flight management, autopilot and autothrottle system control laws, and mode transition logic. Probabilistic estimates of aerodynamic coefficients are used in a high-fidelity model-based computation of the trim envelope. The maneuverability limitations of the aircraft are determined through a robust reachability analysis (relative to the trim envelope). These prediction and assessment technologies are used to trigger timely alerts to detect and avoid loss-of-control situations. Maneuvering envelope limits and the predicted trajectory are indicated on existing flight displays. These display features and alerts were evaluated in the Advanced Concepts Flight Simulator at NASA Ames Research Center, where commercial airline crews flew multiple problematic approach and landings scenarios. Results show that the technologies have the potential to improve situational awareness.