Fly-By-Wire

Abstract

The introduction of fly-by-wire (FBW) flight control systems has been a watershed development in aircraft evolution as it has enabled technical advances to be made, which were not possible before. It is explained how an FBW system provides high-integrity automatic stabilisation of the aircraft to compensate for the loss of natural stability and thus enables a lighter aircraft with a better overall performance to be produced. It also provides the pilot with very good control and handling characteristics, including ‘carefree manoeuvring’, which are consistent and safe over the whole flight envelope. While FBW concepts are not new (guided missiles use them), what has taken the time is the development of failure survival technologies to enable high-integrity systems to be implemented economically with the required safety level, reliability and availability. A major factor has been the development of failure survival digital flight control systems with the associated software development complexity. Most modern fighter aircraft, such as the Eurofighter Typhoon and many modern civil aircraft from Airbus and Boeing exploit FBW control. Further, FBW flight control can also be applied to helicopters to produce a flight control system of very high integrity. The application of active sticks (inceptors) and throttles is described as a means of providing feedback to the pilot.