PIPER PA-28-160

Full Narrative

On February 5, 2023, at 1255 central standard time, a Piper PA-28-180, N9770J, was destroyed when it was involved in an accident near Eau Claire, Wisconsin. The commercial pilot and two passengers were uninjured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.
The pilot stated that he last flew the airplane on December 4, 2022, during which time the airplane started and flew with no anomalies. On December 25, 2022, he was unable to start the airplane for a flight, which he attributed to the outside air temperature of -7oF.
On the day of the accident, the pilot attempted about six engine starts before the battery died and, once the battery was recharged, he attempted an additional six engine starts before he ceased 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 ¼ inch forward during each start. At times during the start attempts, he placed the mixture control into idle cutoff and ran the engine starter. He stopped trying to start the engine and decided to contact an aircraft mechanic. The pilot and the passengers exited the airplane, and 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.