Piper PA-24-180 N6989P accident near Humboldt, Tennessee

Probable cause

A partial loss of engine power due to contaminated fuel.

NTSB analysis

New avionics had just been installed in the airplane after a 5 week wait, and the purpose of the accident flight was for the pilot to test fly the airplane with the installing mechanic. The pilot performed an uneventful preflight inspection of the airplane and after liftoff there was a reduction in engine rpm before the engine lost power completely. The pilot preformed a forced landing to a golf course, resulting in substantial damage to the fuselage and both wings. No mechanical anomalies were discovered during a postaccident examination of the engine that would have precluded normal operation; however, a fuel sample from the carburetor bowl displayed a cloudy (green/yellow) tint instead of the expected clear, blue coloring of aviation fuel. No other contamination was observed within the airplane’s fuel system and the source of the contamination could not be identified. Given this information, it is likely that the engine lost power due to contaminated fuel that migrated through the fuel system into the carburetor.

Text from the NTSB. Open the NTSB docket for ERA20LA198 for the full record.