Editing Aircraft flight control system (section)

===Mechanical===
[[File:Tiger cables.JPG|thumb|right|[[de Havilland Tiger Moth]] elevator and rudder cables]] 
Mechanical or manually operated flight control systems are the most basic method of controlling an aircraft. They were used in early aircraft and are currently used in small aircraft where the aerodynamic forces are not excessive. Very early aircraft, such as the [[Wright Flyer|Wright Flyer I]], [[Blériot XI]] and [[Fokker Eindecker]] used a system of [[wing warping]] where no conventionally hinged control surfaces were used on the wing, and sometimes not even for pitch control as on the Wright Flyer I and original versions of the 1909 [[Etrich Taube]], which only had a hinged/pivoting rudder in addition to the warping-operated pitch and roll controls.<ref>Taylor, 1990. p. 116.</ref> A manual flight control system uses a collection of mechanical parts such as pushrods, tension cables, pulleys, counterweights, and sometimes chains to transmit the forces applied to the cockpit controls directly to the control surfaces. [[Turnbuckle]]s are often used to adjust control cable tension. The [[Cessna Skyhawk]] is a typical example of an aircraft that uses this type of system. [[Gust lock]]s are often used on parked aircraft with mechanical systems to protect the control surfaces and linkages from damage from wind. Some aircraft have gust locks fitted as part of the control system.<ref>Thom,1988. p. 153.</ref>
 
Increases in the control surface area, and the higher airspeeds required by faster aircraft resulted in higher aerodynamic loads on the flight control systems. As a result, the forces required to move them also become significantly larger. Consequently, complicated mechanical [[gear]]ing arrangements were developed to extract maximum [[mechanical advantage]] in order to reduce the forces required from the pilots.<ref name="Taylor118">Taylor, 1990. p. 118.</ref> This arrangement can be found on bigger or higher performance [[Propeller (aircraft)|propeller]] aircraft such as the [[Fokker 50]].

Some  mechanical flight control systems use [[servo tab]]s that provide aerodynamic assistance. Servo tabs are small surfaces hinged to the control surfaces. The flight control mechanisms move these tabs, aerodynamic forces in turn move, or assist the movement of the control surfaces reducing the amount of mechanical forces needed. This arrangement was used in early piston-engined transport aircraft and in early jet transports.<ref>Thom,1988. p. 86.</ref> The Boeing 737 incorporates a system, whereby in the unlikely event of total hydraulic system failure, it automatically and seamlessly reverts to being controlled via servo-tab.