What happened
While operating in instrument meteorological conditions, the aircraft experienced a loss of communication with air traffic control. Before contact was lost, controllers instructed the pilot to verify the aircraft's altitude, at which point radar indicated the plane was approximately 400 feet below its assigned level. The pilot's final transmission indicated that the autopilot had been disconnected and that they were attempting to correct the flight path.
Following this transmission, radar tracking showed the aircraft entered a descending right turn at an average rate of 1,276 feet per minute. This was followed by a rapid climbing left turn, with an average climb rate of 5,423 feet per minute. During this maneuver, the radius of the left turn decreased until radar contact was lost at an altitude roughly 500 feet below the previously assigned level.
A witness observed the aircraft maneuvering below the cloud layer, noting a sharp pull-up followed by a sudden pitch-down before the plane struck the ground. The impact occurred in a field where utility poles and wires crossed the flight path. The aircraft exploded and burned upon impact, and the wreckage was destroyed.
Findings
Investigations into the aircraft and its systems revealed no mechanical anomalies or failures. However, the Pilot's Operating Handbook notes that if excessive up-elevator pressure is applied while the autopilot is active, the system will trim the aircraft nose-down to counter the force. This mechanism is a known characteristic of the autopilot system's response to sustained elevator overpower.