Cessna 180 N3135D accident near Seeley Lake, Montana

Probable cause

The loss of engine power due to fuel starvation as a result of unporting of the fuel.

NTSB analysis

The accident pilot reported that he had topped the airplane off with fuel before departure. Following an uneventful flight, the pilot began a descent to the airport traffic pattern and enrichened the mixture and applied carburetor heat. While on the downwind for the runway, he noted that he had about 10.5 to 11 gallons of fuel remaining. The pilot conducted a low approach by descending over the runway using an intermediate power setting to inspect the runway for wildlife. As the pilot initiated a climb and turned onto the left crosswind leg, the engine lost all power about 300 ft above ground level, and he initiated a forced landing to a nearby clearing. Subsequently, the airplane impacted trees and came to rest in a nose-low attitude.

Examination of the recovered airframe and engine revealed no evidence of any preexisting mechanical malfunction that would have precluded normal operation.

The reported fuel level would have placed the fuel levels in both fuel tanks below 1/4 tank, which would prohibit takeoff according to the airplane owner’s manual. It’s likely that following the low pass over the runway, with the application of power and a climbing turn, the fuel was unported and interrupted the fuel delivery to the engine, which resulted in a loss of engine power.

Text from the NTSB. Open the NTSB docket for WPR22LA337 for the full record.