Grumman Acft Eng Cor-Schweizer G 164A N6743Q accident near Fairview, Kansas

Probable cause

The backfire of the engine and its loss of power for reasons that could not be determined based on the available evidence.

NTSB analysis

The pilot reported that, while the airplane was cruising at 600 feet above ground level, the engine backfired and experienced a partial loss of power. He subsequently made an emergency landing to a road. During the landing, the engine experienced a total loss of power, and the airplane stalled, which resulted in a bounced hard landing. The airplane then slid sideways into a telephone pole, which resulted in damage to the wings and fuselage.

Due to impact damage, an engine test run could not be conducted. The induction air filter was found distorted outward and opposite from the direction of normal airflow, which is indicative of an engine backfire. A postaccident engine examination revealed that the No. 2 cylinder oil control ring was broken. However, it could not be determined when the oil control ring was broken or if the engine backfiring allowed the ring to break. No other anomalies with the engine were noted. The reason for the engine backfire and subsequent loss of power could not be determined.

Text from the NTSB. Open the NTSB docket for CEN14LA375 for the full record.