What happened
After landing at Watertown, the pilot performed cargo loading and unloading operations but did not exit the aircraft. Upon departure, a witness observed the airplane flying over the runway at an altitude of approximately 50 feet AGL. The aircraft was noted to be bouncing and buffeting during this phase. At the time, weather conditions were reported as overcast with occasional snowflakes. Following this period of instability, the airplane descended, impacted the terrain, and exploded.
The investigation
Post-accident inspections of the wreckage identified a ridge of rime ice, measuring between 1/2 to 3/4 inch in thickness, along the leading edge of the left horizontal stabilizer. Additionally, arc-shaped pieces of ice were discovered along the debris path. A mechanical inspection of the engine and airframe found no evidence of any preimpact failure or malfunction that would have prevented the aircraft from maintaining flight.