Cessna 120 N89809 accident near Montague, Massachusetts

Probable cause

The pilot's delay in performing a rejected takeoff after experiencing an intermittent loss of engine power, which resulted in a runway excursion.

NTSB analysis

The pilot reported that, during the takeoff roll, as the airplane accelerated to 40 mph, the engine sputtered, and he reduced power with sufficient runway remaining to stop; however, the sputtering ceased, and he then added power to continue the takeoff attempt. The engine sputtered a second time, and the pilot reduced engine power again. At that point, he was concerned about the length of runway remaining and elected to steer off the left side of the runway, rather than risk going off the end of the runway and down into a ditch. As the airplane departed the left side of the runway, it struck a runway sign and sustained substantial damage to the aft fuselage and empennage. The pilot subsequently defueled and moved the airplane before it could be examined. Therefore, it was not possible to verify the fuel quantity or determine if any fuel contamination was present. Postaccident examination of the airframe and engine did not reveal evidence of any preimpact mechanical failures. The pilot reported that he should have aborted the takeoff earlier.

Text from the NTSB. Open the NTSB docket for ERA12CA118 for the full record.