Widerøe Flight 933, also known as the Mehamn Accident (Norwegian: Mehamn-ulykken), was the crash of a de Havilland Canada DHC-6 Twin Otter operated by Norwegian airline Widerøe. The Twin Otter crashed into the Barents Sea off Gamvik, Norway on 11 March 1982 at 13:27, killing all fifteen people on board. The results of the four official investigations were that the accident was caused by structural failure of the vertical stabilizer during clear-air turbulence.