Cessna 150 N3059X accident near Arden, North Carolina

Probable cause

The inadequate inspection of the throttle control cable assembly, which resulted in a partial loss of engine power during cruise flight.

NTSB analysis

The student pilot was climbing through 5,100 feet mean sea level when the engine “went to idle.” He attempted to adjust the throttle setting; however, the tachometer continued to indicate 740 rpm. The pilot established best glide speed, declared an emergency, and performed a forced landing into a coal ash pit, during which the airplane nosed over, resulting in substantial damage.

Examination of the engine revealed that the throttle control cable had separated from the throttle control lever and there was no spring installed. The securing hardware (bolt/washer/cotter pin) was not found. It is likely that the absence of the cotter pin was not noted during the annual inspection 15 hours before the accident, which allowed the bolt holding the throttle cable to the throttle control lever to loosen and depart during flight, resulting in an engine power reduction to idle.

Text from the NTSB. Open the NTSB docket for ERA21LA297 for the full record.