Description
An elevator is a primaryflight controlsurface that controls movement about thelateral axisof an aircraft. This movement is referred to as "pitch". Most aircraft have two elevators, one of which is mounted on the trailing edge of each half of the horizontal stabilizer. When a manual or autopilot control input is made, the elevators move up or down as appropriate. In most installations, the elevators move symmetrically but, in somefly-by-wirecontrolled aircraft, they move differentially when required to meet the control input demands. Some aircraft types have provisions to "disconnect" the right and left elevators from one another in the event of a control surface jam while other types use differenthydraulic systemsto power the left and right elevator to ensure at least one surface is operational in the event of hydraulic system failure(s).
B727 Flight Control Surfaces. Source: Wikicommons. Origin: FAA(USA)
Function
The elevators respond to a forward or aft movement of the control column or control stick. When the pilot moves the controls forward, the elevator surface is deflected downwards. This increases thecamberof the horizontal stabilizer resulting in an increase inlift. The additional lift on the tail surface causes rotation around thelateral axisof the aircraft and results in a nose down change in aircraft attitude. The opposite occurs with an aft movement of the flight deck controls.
Related Articles
Further Reading
- Do you really understand how your trim works? Many do not, and why it matters.- A paper written by Captain Alex Fisher for GAPAN. The paper was presented at the Go-Around Safety Forum (GASF) in Brussels in 2013.
