Aircraft flight control system

Flight control has long been taught in such fashion for many decades, as popularized in ab initio instructional books such as the 1944 work Stick and Rudder.

Instead, the pilot just grabs the lifting surface by hand (using a rigid frame that hangs from its underside) and moves it.

The most commonly available control is a wheel or other device to control elevator trim, so that the pilot does not have to maintain constant backward or forward pressure to hold a specific pitch attitude[4] (other types of trim, for rudder and ailerons, are common on larger aircraft but may also appear on smaller ones).

Other secondary flight control systems may include slats, spoilers, air brakes and variable-sweep wings.

Gust locks are often used on parked aircraft with mechanical systems to protect the control surfaces and linkages from damage from wind.

The complexity and weight of mechanical flight control systems increase considerably with the size and performance of the aircraft.

With hydraulic flight control systems, the aircraft's size and performance are limited by economics rather than a pilot's muscular strength.

At first, only-partially boosted systems were used in which the pilot could still feel some of the aerodynamic loads on the control surfaces (feedback).

As the actuator moves, the servo valve is closed by a mechanical feedback linkage - one that stops movement of the control surface at the desired position.

[citation needed] A stick shaker is a device that is attached to the control column in some hydraulic aircraft.

Some aircraft such as the McDonnell Douglas DC-10 are equipped with a back-up electrical power supply that can be activated to enable the stick shaker in case of hydraulic failure.

[15] A fly-by-wire (FBW) system replaces manual flight control of an aircraft with an electronic interface.

Several technology research and development efforts exist to integrate the functions of flight control systems such as ailerons, elevators, elevons, flaps, and flaperons into wings to perform the aerodynamic purpose with the advantages of less: mass, cost, drag, inertia (for faster, stronger control response), complexity (mechanically simpler, fewer moving parts or surfaces, less maintenance), and radar cross section for stealth.

Notable efforts have also been made by FlexSys, who have conducted flight tests using flexible aerofoils retrofitted to a Gulf stream III aircraft.

[20][21] In this use, active flow control promises simplicity and lower mass, costs (up to half less), and inertia and response times.

A typical aircraft's primary flight controls in motion
Cockpit controls and instrument panel of a Cessna 182 D Skylane
Blériot VIII at Issy-les-Moulineaux , the first flightworthy aircraft design to have the initial form of modern flight controls for the pilot
de Havilland Tiger Moth elevator and rudder cables
Hydromechanical designs, consisting of a mechanical circuit and a hydraulic circuit, were used to reduce the complexity, weight, and limitations of mechanical flight controls systems. [ 9 ]