What happened
A commercial pilot and a biologist were operating a CFR Part 91 government flight to conduct fish surveys in remote regions of the Alaska Peninsula. The flight departed from a location approximately 51 miles southwest of the accident site. At the time of departure, weather conditions consisted of calm winds and small clouds over high, mountainous terrain.
As the survey progressed into a coastal bay area on the east side of the peninsula, winds began blowing from the southwest, creating disturbances on the water surfaces of bays and streams. Due to changing conditions, the pilot decided to terminate the survey and return to the departure airport, heading in a southwest direction. During this return flight, wind speeds increased alongside occasional turbulence.
While cruising at approximately 1,200 feet MSL near a small saddle between two low hills, the aircraft encountered a strong downdraft that caused a loss of altitude. Despite the pilot applying full power, the descent continued. The pilot observed trees below being flattened by the downward air movement. In an attempt to maneuver away from one side of a hill, a sharp increase in ground speed forced the pilot to turn back into the prevailing wind.
As the aircraft continued toward the terrain, the pilot lowered the nose into an area of tall alders to ensure the impact with the ground occurred with some degree of control. The collision with the trees caused the engine and firewall to be torn from the front of the aircraft and resulted in the wings being displaced rearward. The passenger noted that the force of the downdraft was strong enough to pin a clipboard against the cabin roof.
At the time of the accident, an automated weather station 35 miles west of the site reported winds from 240 degrees at 36 knots with gusts up to 41 knots. The occupants of the aircraft were not injured.