Incident Overview
Approximately 30 minutes before starting engines, the crew had started the auxiliary power unit (APU). While starting the number 2 engine, the crew smelled smoke and turned to observe smoke in the cabin. The crew immediately shut down the number 2 engine, the APU, and all electrical switches. The crew and four passengers evacuated the airplane through the main cabin door.
Inspection Findings
An inspection of the airplane revealed that a venturi fan unit motor, located aft of the rear cabin bulkhead, had overheated and failed. Components and wiring in the vicinity of the venturi were charred. No other anomalies were found.
Venturi Fan Unit History
The venturi fan unit was identified as an older model. In 1994, this model was noted to be subject to fan motor overheating, and an Airworthiness Directive (AD) was issued requiring inspection of the units every four years. The unit installed on the incident airplane was installed in 1999.