Incident Summary
While the pilot held the aircraft short of the runway in preparation for takeoff, a fire was observed emanating from beneath the right wing. The pilot immediately alerted airport rescue and firefighting (ARFF) personnel and evacuated the airplane. Firefighters responded and extinguished the fire.
Examination Findings
Post-incident examination determined that the fire had originated from the right wheel assembly, not from the wing itself. Inspection of the wheel revealed that the brake seals were worn and the brake fluid reservoir was empty. The brake linings and discs exhibited heavy scouring. Furthermore, the brake pads had not been replaced in over 400 hours of operation.
Maintenance History
The master brake cylinder had been replaced eight days prior to the incident during an annual inspection. No other recent maintenance actions related to the braking system were noted.