What happened
While taxiing toward the end of a taxiway, the pilot of a Cessna 180 applied the brakes periodically to maintain a slow speed. The engine RPMs were maintained at less than 1,000. After crossing the active runway, the pilot traveled approximately 1.5 miles down the taxiway and set the parking brake to begin the pre-flight run-up.
During the control check, the pilot observed smoke emanating from underneath the left wing. Upon inspection, the pilot discovered smoke coming from the wheel area, which escalated into a small fire on the disc brakes approximately 30 seconds later. The pilot shut down the engine and exited the aircraft to call for assistance. A ground worker arrived in a pickup truck with a fire extinguisher and successfully extinguished the flames. The pilot was not injured, but the aircraft sustained substantial damage.
The investigation
Investigators examined the aircraft's brake system and found no mechanical anomalies.