Aviation Accident Summaries

Aviation Accident Summary ANC09LA038

Bethel, AK, USA

Aircraft #1

N629SP

CESSNA TU206

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.

Factual Information

On May 6, 2009, at 0903 Alaska daylight time, a single engine Cessna TU206F airplane, N629SP, sustained substantial damage when it collided with terrain during takeoff at the Bethel Airport, Bethel, Alaska. The airplane was being operated by Alaska Scenic Air LLC, Eagle River, Alaska, as a visual flight rules (VFR) on-demand cargo flight, under the provisions of Title 14 Code of Federal Regulations (CFR) Part 135. The solo commercial pilot sustained minor injuries. Visual meteorological conditions prevailed at the airport, and company flight following procedures were in effect. The flight was en route to Kasigluk, Alaska. 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. An FAA inspector, who responded to the scene, said the nose gear collapsed and there was structural damage to the firewall, forward empennage, and both wingtips. The left wing had a significant buckle at wing station 100, causing the outboard leading edge skin to open up and the inboard inner spar skin to buckle downward. At 0853, an aviation routine weather report (METAR) at Bethel, Alaska, reported wind from 330 degrees at 8 knots, 10 miles visibility, few clouds at 700 feet, temperature 27 degrees, dew point 23 degrees, and an altimeter setting of 29.93 inches of Mercury.

Probable Cause and Findings

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.

 

Source: NTSB Aviation Accident Database

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