The pilot told investigators that he last flew the Piper PA-28-160 on Dec. 4, 2022, during which time the airplane started and flew with no anomalies. On Dec. 25, 2022, he was unable to start the airplane, which he attributed to the outside air temperature of -7°F in Eau Claire, Wisconsin.
On Feb. 5, 2023, the day of the accident, he attempted six engine starts before the battery died and, once the battery was recharged, he attempted an additional six engine starts before he stopped further attempts to start the engine.
He said that during each engine start attempt he applied engine primer three times and pumped the throttle control two times. The throttle control was positioned about 1/4-inch forward during each start.
At times during the start attempts, he placed the mixture control into idle cutoff and ran the engine starter.
The pilot finally gave up and he and his passengers got out of the airplane. That’s when one of the passengers saw a small flame inside the engine cowl. The pilot told the remaining passenger to move the mixture control to idle cutoff. The fuel selector was not turned to the off position.
The flames continued to spread and the airplane was destroyed by the fire.
A photo showed flames during the accident in two areas. The first area was beneath the engine and the second area was near the right aft top side of the engine by the right forward fuselage.
Examination of the engine compartment in the first area revealed that the carburetor airbox assembly and the carburetor heat assembly were consumed by fire. The fuel line leading to the carburetor was intact.
The area above the carburetor exhibited soot consistent with lower combustion temperatures above a hotter area, which lacked soot and was around the carburetor bowl.
Examination of the second area revealed a separated and thermally damaged engine primer line for the No. 3 cylinder. The remainder of the engine primer lines were intact. The area near the separated primer line did not contain a comparable amount of soot as that of the area further from the separated primer line.
Fire damage precluded determination of the fuel and ignition sources of the fire.
Probable Cause: The engine fire that began for undetermined reasons following numerous engine start attempts.
NTSB Identification: 106682
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This February 2023 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
