Engine Seizure During Cruise Flight After Prop Overspeed (N9467N)

Incident Summary

Five minutes after departure, during normal cruise flight, a certified flight instructor observed a propeller overspeed. He immediately pulled back on the propeller control to reduce engine RPM and directed the student, a private pilot, to divert to the airplane's home base. Two minutes after the overspeed, the engine sputtered for five seconds and seized. The instructor took control and executed a forced landing on a hillside. During the landing, the airplane brushed small branches at the top of a tree and collided with the terrain. The pilot stated that he used all available airspeed to reach a suitable landing spot and could not flare to cushion the landing.

Investigation Findings

An examination of the engine revealed evidence of oil exhaustion. The oil quick drain was found to be in the open and locked position. A review of maintenance records showed that the drain was the incorrect part. Additionally, there was an airworthiness directive concerning the incorrect oil drain being opened by contact with the landing gear during retraction.