Fly‐by‐Wire Flight Control Systems

Abstract The early generation of flight control systems were entirely mechanical and used rods and levers, or cables and pulleys, to provide direct mechanical linkages between the pilot's cockpit controls and the control surfaces that maneuver the aircraft. As technologies developed and aircraft evolved in size and speed, the mechanical systems were developed to include fully power‐operated controls. The desire for improved aircraft handling and the need to automate some phases of flight, made it necessary to add signals from the stability augmentation systems and autopilot, to the basic manual control circuits. Eventually, the direct mechanical linkages between the cockpit controls and the actuators were replaced with electrical signalling and computers, leading to the term “fly‐by‐wire”. This arrangement allows the pilot to directly command the aircraft's motion, rather than by commanding the control surface angles needed to achieve the motion. This chapter provides an overview of some of the technologies and processes used for the design and qualification of fly‐by‐wire systems, including aerodynamics and flight control, system hardware and implementation, flight control laws, piloted simulation and aircraft handling, ground and flight testing, the benefits of fly‐by‐wire and future system developments.