Incident Overview
A non-instrument rated private pilot departed a non-towered airport for a 131-nautical mile cross-country flight. Approximately 55 miles from the departure airport, the pilot reported an autopilot/runaway trim problem to an air traffic controller. The pilot then turned back toward the departure airport and informed the controller that he was pulling circuit breakers and did not require assistance. He noted that the issue had been intermittent in the past.
Radar Observations
Radar data showed a normal departure followed by a 180-degree turn back toward the departure airport. The return track was a straight line with little variation in altitude or airspeed. Upon reaching the airport, the airplane descended to 2,200 feet mean sea level and proceeded northwest, just beyond the airport. For the next 52 minutes, the airplane executed a series of irregular, non-uniform circuits, alternating left and right turns, climbs, and descents. The first circuits were within about 5 miles of the airport, while the final series occurred within a roughly 10-mile radius.
Accident Sequence
There were no witnesses to the accident. Emergency personnel located the crash site approximately 1 mile short of the approach end of the active runway, shortly after the airplane disappeared from radar. Impact marks on trees indicated the airplane struck trees and terrain in a near wings-level attitude at cruise speed. The flaps were retracted; the landing gear position could not be determined.
Examination Findings
Post-accident examination of the airframe and engine revealed no evidence of any malfunction or pre-impact anomaly. The elevator trim tab drive mechanism measured 2 inches, corresponding to approximately a 15-degree tab-up (nose-down) pitch setting. A post-crash fire consumed most of the airplane. The reason for the controlled flight into the ground could not be determined.
Weather Conditions
At the time of the accident, winds were reported from 180 degrees at 14 knots, gusting to 19 knots.