Fail-Safe Design of Computerized Aircraft Flight Control Systems: Theory, Practice and Application to Accident Investigation
Modern computerized "fly-by-wire" flight control systems provide improved flight safety and stabilization over manual flight control systems. Fly-by-wire systems are typically electronically controlled and hydraulically actuated and complete electronic control/actuation systems are planned for the next generation of commercial aircraft.
Some challenges of piloting fly-by-wire systems include the possibility of sudden loss of automated flight control (autopilot) due to computer and sensor failure. Despite the highly redundant design of the control systems, hardware failures combined with pilot error can result in loss of aircraft stability. An overview of fly-by-wire control systems will be presented with an emphasis on reliability and redundancy design concepts for airliner safety. The fatal crash of Air France flight 447 in 2009 will be used as a case study to demonstrate how computerized flight control can fail, the response of pilots, and the investigation process.