Departure and Initial Conditions
The aircraft departed Shemya Airport at 0810 local time for a brief 10-minute flight to the Casco Grove Coast Guard Station (LORAN Station) on Attu Island. Weather at departure was reported as good, with a ceiling of 400 feet broken clouds, visibility of eight miles, and winds from 210 degrees at 20 knots. Due to the short duration of the flight, the crew did not align the aircraft's inertial navigation system before takeoff.
Approach and Descent
Upon arrival near Casco Grove Airport, the weather had deteriorated. The captain chose to maintain visual contact with the water surface, while the copilot and navigator monitored the approach using radar. As the crew conducted the approach, they did not recognize that their altitude was too low.
Collision and Aftermath
The aircraft struck the slope of a mountain located approximately three miles southwest of runway 02 threshold. The impact destroyed the aircraft and ignited a fire. A crew member and one passenger sustained fatal injuries, while nine other occupants were injured.
Cause
The probable cause of the accident was the crew's failure to realize their altitude was too low during the approach.