Casualties unknown

2001-07-24: Boeing STEARMAN PT-17 (N56920) — Anniston, AL

Anniston, AL, US

On July 24, 2001, a Boeing STEARMAN PT-17 (registration N56920) was involved in an aviation accident near Anniston, AL. Investigators recorded the probable cause as: The inadvertent activation of the flight control gust locks by the pilot rated passenger that resulted in the loss of control inflight. Contributing was the pilot in commands failure to follow the airplane's pre-flight inspection check list. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 1781061362Data APIEditorial standards

Witnesses reported an airplane circling a golf course, then climbing before entering a nose-down slow spin and impacting trees. Post-crash examination revealed the control surface lock was in the locked position, contrary to pre-takeoff procedures.

Accident Sequence

According to witnesses, the airplane was circling a golf course before beginning a climb. Shortly after reaching an undetermined altitude, the airplane entered a nose-down slow spin and subsequently impacted a stand of trees.

Pre-Accident Examination

On July 22, 2001, the two other owners of the airplane inspected the control surface lock, also known as a gust lock, by moving it between the lock and unlock positions several times. This inspection was conducted in preparation for the upcoming annual inspection. The owners stated they could not recall whether they had stowed the lock in the unlock position after completing their inspection.

Post-Accident Findings

Examination of the flight controls revealed that the handle for the control surface lock, which secures the rudder, ailerons, and elevator, was installed in each cockpit. After the accident, the locking handle in the forward cockpit was found separated from its mounting bracket, but when aligned with the fracture surface, it was determined to be in the locked position. The aft control lock was found intact and in the down and locked position. Injuries sustained by a pilot-rated passenger's left arm were consistent with damage to the forward control lock.

Operating Procedures

According to the Pilots Flight Operating Instructions, the control lock should be in the lock position during startup and taxi, and should be disengaged and stowed in the unlock position just prior to takeoff.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20010731X01560. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.