Cessna TU206 N629SP accident near Bethel, Alaska

Probable cause

The pilot’s failure to remove visible frost from the wings during the preflight inspection, and his failure to maintain adequate airspeed to avoid a stall. Contributing to the accident were conditions conducive to structural icing/frost.

NTSB analysis

The airplane was taking off on the first flight of the day and had accelerated normally during the short field takeoff roll. During entry into the initial climb, the airplane suddenly rolled into an uncommanded left bank and entered an uncontrolled descent. The left wingtip struck terrain to the left of the runway approximately 1,000 feet from the beginning of the takeoff roll. The airplane came to rest upright approximately 200 feet from the initial impact point. During the impact sequence the unsecured cargo shifted forward and struck the back of the pilot’s seat and the right side of the instrument panel. The pilot exited the airplane unassisted. Photos taken 5 minutes after the accident show the leading edges and tops of the wings, and horizontal tail surfaces were covered in rough frost. The photos also show the frost appears to have been scraped off of most of the windshield. There was substantial damage to the left wing, nose gear, firewall, forward empennage, and both wingtips.

Text from the NTSB. Open the NTSB docket for ANC09LA038 for the full record.