D.B. Cooper (1981): Cooper vane era

After the passenger release, Cooper sent the remaining crew forward and used the aft stairs — a feature of the 727 that could be opened in flight. Crew instruments later showed a change consistent with a person leaving the aircraft. The jump zone was reconstructed from flight-path data as a corridor over Ariel, Washington, and the Lewis River country, later expanded as wind and timing models changed.

A Portland reporter mixed the ticket name with a local man named D.B. Cooper; wire services kept the error. The FBI composites — especially the 1972 and 1973 sketches — became the American face of an unidentified hijacker. Agents interviewed thousands of people. Richard Floyd McCoy Jr., who hijacked a different airliner in 1972, was a much-cited lookalike; the Bureau did not treat him as Cooper.

Special Agent Ralph Himmelsbach, who stayed with NORJAK for years, later wrote that the jumper faced night, rain, timber and a thin chance of walking out with the money. That is an investigator’s memoir, not a finding that Cooper died. The 2016 suspension cited the age of the case and the death or fading of witnesses, not a recovered body.