Gust lock

A gust lock on an aircraft is a mechanism that locks control surfaces in place preventing random movement and possible damage of the surface from wind while parked. Gust locks may be internal or external.

Safety

A gust lock can pose a serious safety hazard if its removal is omitted before an aircraft's takeoff because it renders the flight control inoperative.

The very first example built of the Boeing B-17 Flying Fortress, the initial Model 299 aircraft, was lost in just this way on October 30, 1935, when its self-contained gust locks were left engaged, with the resulting crash killing Boeing chief test pilot Leslie Tower, and United States Army Air Corps test pilot Ployer Peter Hill. Less than a year later, Nazi German Luftwaffe Generalleutnant Walter Wever lost his life in a similar accident from gust lock neglect, when his Heinkel He 70 Blitz monoplane crashed on June 3, 1936 from the Blitz's aileron gust locks not being disengaged before takeoff. Prince Gustaf Adolf of Sweden, the American singer and actress Grace Moore and 21 others were killed in 1947 during the crash of a KLM flight at Copenhagen Airport due to the flight crew forgetting to disengage the gust lock on the tail fin of the aircraft.

For this reason, gust lock disengagement is a very important step on the takeoff checklist for those aircraft equipped with gust locks.

References

"Gust lock". The Illustrated Encyclopedia of Aviation and Space. 6. Los Angeles: A.F.E. Press. 1971. pp. 1043. LCCN 68-14013.