What happened
The aircraft sustained minor damage after an electrical fire occurred in flight. The incident took place while the aircraft was in cruise flight at 9,000 feet mean sea level. The pilot reported observing smoke emanating from the circuit breaker panel mounted on the left side wall of the cockpit. As the situation developed, several circuit breakers popped, resulting in the loss of the majority of the electrical system. In response to these failures, the pilot elected to execute a precautionary landing at an airport nearby.
The investigation
Post-incident examination revealed that fire and heat damage was limited to the left side electrical panel, primarily affecting the upper circuit breaker panel. Investigators identified two suspect areas as possible points of origin for the fire. One potential cause was a burned-up resistor on the trim cowl flap indicators which had a disconnected wire to a diode. The other suspect area was a bus bar link that was installed backwards and had come into contact with a fuselage bulkhead, causing it to short out.
Findings
Despite identifying two distinct mechanical anomalies, investigators were unable to make a conclusive determination as to which specific component caused the incident fire. Both the resistor failure on the trim cowl flap indicators and the misinstalled bus bar link presented plausible origins for the electrical fault that led to the in-flight smoke and system loss.