Cooper vane

Animation showing how D. B. Cooper left the hijacked airplane; now, the Cooper vane makes this impossible.
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.[1]

  1. ^ Cite error: The named reference Gladwell-2001-10 was invoked but never defined (see the help page).