The apparent success and instant notoriety of the hijacker known as D. B. Cooper in November 1971 resulted in over a dozen copycat hijackings within the next year all using a similar template to that established by Cooper. Like Cooper, the plan would be to hijack an aircraft, demand a ransom, and then parachute from that aircraft as a method of escape. To combat this wave of extortion hijackings, aircraft were fitted with eponymous "Cooper Vanes", specifically designed to prevent the aft staircase from being lowered in-flight. The Cooper Vane, as well as the widespread implementation of other safety measures such as the installation of metal detectors throughout American airports, would spell the end of the Cooper copycats.