Accident Overview
During preparation for landing, the pilot turned onto the base leg and adjusted the mixture, propeller, and throttle controls to full forward. At that moment, the engine experienced a complete loss of power. The pilot attempted to restart the engine but was unsuccessful. Due to the low altitude, the pilot determined that reaching the runway was not possible and opted to land on a dirt road. During the landing roll, the left wing collided with a fence post.
Examination Findings
A post-crash inspection of the engine revealed that the spark plugs for two cylinders were fouled, and the piston heads for those cylinders were black with excessive carbon build-up. The fuel metering unit was bench-tested. At the high RPM setting, both the fuel pump pressure and the fuel flow pressure were found to be excessively out of limits. Additionally, contamination resembling rubber or gasket-like material was observed on the fuel control valve and the manifold valve screens. This same substance was also found under and around the seat area on the fuel pump. Large amounts of particles were discovered inside the pump return fitting.