Accident Details
The pilot landed at Watertown to load and off-load cargo before departing without exiting the aircraft. A witness observed the airplane over the runway at approximately 50 feet above ground level, describing it as bouncing and buffeting. Another witness reported overcast skies with occasional snowflakes. The airplane subsequently descended, struck the terrain, and exploded.
Investigation Findings
Post-accident examination discovered a ridge of rime ice measuring between 1/2 and 3/4 inch thick along the leading edge of the left horizontal stabilizer. Pieces of arc-shaped ice were scattered along the wreckage path. Inspection of the wreckage revealed no preimpact failures or malfunctions of the engine or airframe that would have prevented continued flight.
Probable Cause
The official probable cause was determined to be the pilot's failure to perform an aircraft preflight and to remove ice that had accumulated on the airframe. A contributing factor was the presence of icing weather conditions and the ice that had accumulated on the airplane.