Sequence of Events
A private pilot, who also held an Airframe and Powerplant (A&P) mechanic certificate, and a passenger departed on a cross-country flight. During the initial climbout, the pilot detected a burning odor and decided to return to the airport for landing. White smoke entered the cockpit, followed by black smoke and a small flame beneath the instrument panel. While on short final approach, the engine lost power, and the pilot could not see outside the airplane due to the smoke filling the cabin. The airplane touched down, and the occupants evacuated without injury. The airplane continued to burn and was destroyed.
Wreckage Examination
Post-accident examination of the wreckage revealed that a worn exhaust system clamp had come loose. The exhaust pipe subsequently became disconnected, directing hot gases onto the voltage regulator. The electrical wiring on the regulator burned and shorted, initiating an electrical fire that spread to the cabin.
Maintenance History
The pilot/mechanic had purchased the airplane three months before the accident, following an annual inspection. The maintenance log books were not recovered; therefore, verification of the last inspections and compliance with an FAA airworthiness directive requiring exhaust system inspection every 50 hours could not be confirmed.