Fault detection of a flight control computer in a harsh electromagnetic environment

Abstract

Verifying functional integrity of flight control computers (FCC) in harsh electromagnetic environments is a key issue in development, certification, and operation of systems performing flight critical functions. A strategy is being developed for real-time detection of control command errors caused by electromagnetic environments in FCCs during validation testing. A system level approach to FCC fault detection and mitigation in real time is proposed. Monitoring the health of the FCC based on analysis of simplex flight path data is proposed. This data are collected during nominal closed loop tests of an AlliedSignal quad-redundant FCC interfaced to an emulation of the aircraft engines, sensors, and actuators, and running B737 Autoland control laws. Each flight entails the aircraft landing during disturbances associated with wind gusts. Sensor inputs and command outputs for every frame are stored for each flight. System Identification techniques are applied to the data to approximate nonlinear models for the commands.