What happened
During an instrument flight rules (IFR) cross-country flight, an aircraft was cruising at 20,000 feet when the pilot initiated a course reversal. During a communication with air traffic control, the pilot reported a loss of altitude and a need to climb. When questioned by the controller regarding the nature of the emergency, the pilot stated that the autopilot had failed. Shortly after this exchange, radar contact with the aircraft was terminated.
A witness observed the aircraft descending toward the ground while on fire. The subsequent investigation revealed a debris field spanning more than 3 miles through a wooded area. The wreckage was highly fragmented; the main site contained the heavily burned left engine, left propeller, left wing, and the empennage. The right wing was found 1/4-mile north of the primary site, having separated at the wing root. Additionally, the vertical and horizontal stabilizers were located approximately 3/4-mile north of the main wreckage.
Findings
Examination of the wreckage fractures showed overstress characteristics, which are consistent with an in-flight breakup. Analysis of the debris path suggested that the tail components likely detached from the aircraft first, followed by the separation of the right wing. The investigation determined that this structural failure caused the deformation and eventual loss of the stabilizers.
Because the stabilizers showed no signs of heat damage, investigators concluded that their separation preceded the fire. The fire observed by the witness was likely a consequence of the structural failure itself. No evidence of mechanical malfunctions or failures occurring prior to the breakup was identified during the examination of the wreckage. The accident resulted in two fatalities.