Background
A scheduled commuter flight operated by a certificated commercial pilot departed with five passengers aboard. The flight was originally scheduled to depart from runway 18 but was delayed for two hours due to ice fog and low visibility, as reported by the pilot.
Accident Sequence
According to the pilot, shortly after taking off from runway 18, the engine surged and subsequently lost power. The pilot executed an off-airport emergency landing. During this landing, the airplane collided with snow-covered terrain. The impact resulted in substantial damage to the propeller, fuselage, and wings.
Examination After the Accident
Following retrieval of the airplane, an FAA airworthiness inspector examined the aircraft and found no mechanical anomalies. While still attached to the airplane, the engine was started and operated at idle. Later, the engine was tested on a test stand and produced full power without issues.
A pilot-rated Alaska State Trooper with extensive experience in the accident airplane make and model inspected the airplane soon after the accident. The trooper reported an accumulation of frost on the wings, horizontal stabilizer, and elevators.
Probable Cause
The official probable cause was determined to be the pilot's failure to remove frost from the airplane prior to flight and an inadvertent stall/mush.