Incident Overview
During maintenance of the engine, just before the annual inspection was signed off, an individual partially loosened and then attempted to tighten the bolt securing the crankshaft gear to the crankshaft. The old lockplate was not replaced and was not properly secured about the bolt.
Engine Failure
As a result of a loose bolt, the dowel pin that aligns the gear with the crankshaft shifted, causing the gear to move out of position. This led to the engine stopping.
Emergency Landing
The pilot failed to lower the wing flaps during the subsequent emergency landing. The aircraft struck a dirt ditch short of the intended landing site.