Casualties unknown

2004-05-02: Cessna U206F (N35860) — Nanwalek, AK

Nanwalek, AK, US

On May 2, 2004, a Cessna U206F (registration N35860) was involved in an aviation accident near Nanwalek, AK. Investigators recorded the probable cause as: A loss of directional control for an undetermined reason during takeoff-initial climb, which resulted in the left wing colliding with the ground. 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

A commercial pilot on an air taxi flight experienced a sudden left roll after lift-off on a gravel runway. The left wingtip struck rocks, causing the airplane to swerve and come to rest on a beach. Postaccident examination revealed asymmetric flap extension but no mechanical malfunction in the wing controls.

Accident Sequence

The commercial-certificated pilot was conducting an on-demand air taxi flight from a remote gravel runway adjacent to a rocky beach. The airplane was equipped with a short takeoff and landing (STOL) modification that droops the ailerons about 16 degrees when flaps are extended. The pilot reported lowering flaps to 20 degrees and applying full power for a short field takeoff with the control yoke aft. As the airplane gained speed, the nose rotated to about 10 degrees above the horizon and the main landing gear tires lifted off the runway surface. At about 3 feet above the runway, the airplane suddenly rolled to the left. The pilot applied right aileron and right rudder to stop the roll, but without effect. The left wingtip then collided with small rocks along the beach approximately 800 feet from the beginning of the runway, causing the airplane to swerve about 30 degrees to the left. The airplane came to rest on the rocky beach, oriented about 150 degrees to the left of the runway centerline. The pilot stated that the engine was producing power throughout the event and did not report any aileron control problem.

Postaccident Examination

Photographs of the accident scene and the airplane showed the left wing bent upward at the tip and the right wing bent upward about midspan. A view from the aft side revealed the left wing flap was extended slightly, while the right wing flap was extended about one-half of its full range. The airplane was recovered by insurance and company personnel and transported to the operator's facility. For transport, the wings, rudder, horizontal stabilizer, and elevator were removed. The NTSB investigator-in-charge examined the wings and found no observed mechanical malfunction of the internal flap and aileron control mechanism within each wing. However, because the wings had been removed for recovery, the rigging of the aileron and flap cables could not be established.

Video Evidence

The right front seat passenger was recording the flight on a hand-held video recorder. Review of a copy of the video tape showed the airplane taxiing at a fast pace toward the departure end of the runway. The airplane made a rolling "U" turn without slowing or stopping, and the pilot applied full power. As the airplane lifted off, it almost immediately rolled to the left and collided with the ground. The video did not record any sound of a stall warning horn nor a view of the flap handle position. The elapsed time from application of full power for takeoff until the left wing collided with the ground was about 17 seconds. Additional video from the passenger's camera recorded after the accident showed the airplane at the point of rest; the left flap appeared slightly extended, and the right flap appeared extended about one-half of its normal travel.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20040506X00563. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.