Cooper vane - WikiHQ

thumb|Animation showing how [[D. B. Cooper left the hijacked airplane; the Cooper vane was created to make this impossible.]]

thumb|The Cooper vane in place on the aircraft. The front of the aircraft is to the bottom left; the vane rotates clockwise through 90 degrees to secure the ramp.

A Cooper vane, also sometimes called a Dan Cooper switch or D.B. Cooper device, is a mechanical aerodynamic wedge that prevents the ventral airstair of an aircraft from being lowered in flight.

</references>