Incident Overview
An aircraft taxied to the runup area for an engine runup. During the runup, the pilot reported that the engine ran rough on one magneto but smooth on the other. The pilot leaned the carburetor mixture, after which the engine stopped.
Restart Attempts and Fire
According to a passenger, the pilot attempted to restart the engine four or five times. During these restart attempts, a fire erupted, and the aircraft was consumed by the fire. Safety inspectors later opined that excess fuel puddling and a backfire had occurred during the restart process.
Engine and Carburetor Condition
The engine and carburetor had accumulated 2,400 hours since their last overhaul, which exceeded the manufacturer's recommended time for the carburetor. The carburetor was too badly damaged by the fire to undergo a flow test.
Firefighting Equipment
No fire extinguisher was on board the aircraft at the time of the incident.