1 fatality

2008-06-18: De Havilland DHC-6 Twin Otter (N656WA) — Wiggins Airways — Hyannis-Barnstable, United States of America

Hyannis-Barnstable, United States of AmericaTakeoff (climb)

On June 18, 2008, a De Havilland DHC-6 Twin Otter (registration N656WA) operated by Wiggins Airways was involved in an aviation accident near Hyannis-Barnstable, United States of America during takeoff. One person was killed. Investigators recorded the probable cause as: The pilot's failure to remove the flight control lock prior to takeoff. Contributing to the accident was the Federal Aviation Administration's failure to issue an airworthiness directive making the manufacturer's previously-issued flight control lock service… This summary draws on records from the Bureau of Aircraft Accidents Archives (B3A); 5 related events involving the same aircraft type or operator are linked below.

Sourcesthe Bureau of Aircraft Accidents Archives (B3A)Primary reportUpdated 1781197394Data APIEditorial standards

A pilot did not remove the flight control lock before takeoff, and the restraint was unfastened. The FAA's delayed airworthiness directive was identified as a contributing factor.

Accident Sequence

The pilot contacted air traffic control and requested taxi clearance approximately one hour after the scheduled departure time. About four minutes later, the flight was cleared for takeoff. A witness observed the airplane taxi and noted it seemed unusual that the airplane did not stop and increase engine power before takeoff. Instead, the airplane taxied directly onto the runway and began the takeoff roll without pausing. The airplane took off quickly, within about 100 yards of beginning the roll, became airborne, and entered a steep left bank. The bank angle increased, and the airplane descended and impacted the ground.

Post-Accident Examination

Examination of the wreckage revealed that the pilot's four-point restraint was not fastened. Additionally, at least a portion of the cockpit flight control lock remained installed on the control column. One of the items on the pre-takeoff checklist was "Flight controls - Unlocked - Full travel." The airplane was not equipped with a control lock design that, according to the airframe manufacturer's previously issued service bulletins, would "minimize the possibility of the aircraft becoming airborne when take off is attempted with flight control locks inadvertently installed."

Regulatory Actions

In 1990, Transport Canada issued an airworthiness directive to ensure mandatory compliance with the service bulletins. However, the Federal Aviation Administration did not issue a similar directive until after the accident.

Probable cause

The pilot's failure to remove the flight control lock prior to takeoff. Contributing to the accident was the Federal Aviation Administration's failure to issue an airworthiness directive making the manufacturer's previously-issued flight control lock service bulletins mandatory.