Validation of Safety-Critical Systems for Aircraft Loss-of-Control Prevention and Recovery

Abstract

Validation of technologies developed for loss of control (LOC) prevention and recovery poses significant challenges. Aircraft LOC can result from a wide spectrum of hazards, often occurring in combination, which cannot be fully replicated during evaluation. Technologies developed for LOC prevention and recovery must therefore be effective under a wide variety of hazardous and uncertain conditions, and the validation framework must provide some measure of assurance that the new vehicle safety technologies do no harm (i.e., that they themselves do not introduce new safety risks). This paper summarizes a proposed validation framework for safety-critical systems, provides an overview of validation methods and tools developed by NASA to date within the Vehicle Systems Safety Project, and develops a preliminary set of test scenarios for the validation of technologies for LOC prevention and recovery.

Online Safe Flight Envelope Prediction for Damaged Aircraft: A Database-driven Approach

“…In this respect, even if the "curse of dimensionality" could be tackled by any chance, determining the new bounds of safe flight envelopes online under abnormal conditions would still remain as one of the main challenges of aircraft loss-of-control prevention and recovery. 3,4 This paper presents an early stage in the development of the new Flight Envelope Anticipative Controller (FENCE) that is being developed at the Control & Simulation division of TU-Delft and provides an innovative process of predicting safe flight envelopes based on advanced database generation and retrieval techniques. Our approach is different from others in many respects.…”

“…There are a wide spectrum of factors and series of events that could potentially give rise to LOC accidents, like vehicle impairments, damages, icing, inappropriate crew responses and vehicle upset, 3 which are deeply coupled and vary under different conditions. Therefore, the definitions of LOC accidents still remain vague and it is not yet possible to find out one single solution that prevents all accidents.…”

“…The National Aeronautics and Space Administration's (NASA) Aviation Safety Program is developing technologies that address aircraft LOC prevention and recovery under a wide range of hazards and uncertain conditions. [3][4][5] Furthermore, some researchers are trying to quantify LOC events from flight data by defining metrics consist of five envelopes that are related to airplane flight dynamics, aerodynamics, structural integrity and flight control use. 6,7 Their results can help investigators decide whether or not the accident should be classified as a LOC, and identify the axis in which each event started as well as the chain of events that led to the lost controls, which will suggest valuable clues on how best to prevent future LOC events.…”

Loss of Control Prevention and Recovery: Onboard Guidance, Control, and Systems Technologies

“…A full discussion of the validation of these technologies is presented in a companion paper (Ref. 30), as well as a preliminary set of LOC test scenarios for use in their evaluation. The LOC test scenarios are representative of the accident set analyzed in Ref.…”

“…This is the subject of a companion paper. 30 Validation of the individual and the integrated technologies is essential in ensuring that they are effective in assuring safe vehicle operations under current and future LOC risks (see Fig. 5), and that they themselves do no harm.…”