Accident Summary
The airplane was destroyed when it impacted the ground while maneuvering at a low altitude following a loss of control in instrument meteorological conditions. The accident occurred during a flight in instrument meteorological conditions when radar and voice contact were lost. No anomalies were found with the airplane or associated systems.
Flight History
Prior to the loss of communication, controllers advised the pilot to check altitude. Radar data showed that the airplane was about 400 feet below the assigned altitude. The pilot responded, "roger sir my auto pilot i just cut off uh correcting immediately." This was the last received transmission. Radar data then indicated a descending right turn at an average rate of descent of 1,276 feet per minute, followed by a climbing left turn with an average rate of climb of 5,423 feet per minute. The radius of the left turn decreased until radar contact was lost about 500 feet above the last assigned altitude.
Witness Account
A witness who saw the airplane just prior to impact described the airplane maneuvering beneath the clouds before pulling up sharply and then pitching down and impacting the ground. The airplane exploded and burned upon impact. There was a utility wire and associated poles running across the airplane's flight path in the field where the wreckage was located.
Autopilot Information
The autopilot section of the Pilot's Operating Handbook states, "Sustained elevator overpower will result in the autopilot trimming against the overpower force." Consequently, if up elevator pressure is applied with the autopilot engaged, the autopilot will trim the airplane nose down.
Probable Cause
The probable cause was the maneuver to avoid the utility wire while maneuvering, resulting in an inadvertent stall and subsequent impact with the ground. Factors were the pilot's inadvertent activation of the elevator trim, resulting in a loss of control during flight in instrument meteorological conditions, as a result of the pilot's lack of knowledge concerning the operation of the autopilot system. Another factor was the utility wire.