Incident Overview
Two commercial licensed pilots, the sole occupants of the aircraft, departed from Baragwanath Airfield for a familiarization flight. After a period of single-engine flight with the starboard propeller feathered, the crew completed two takeoffs and landings. During the approach for the third landing, with the landing gear extended and locked and flaps set to 60°, a noise was heard from the port side.
Sequence of Events
The pilots associated the noise with the landing gear and initiated a go-around. At an indicated speed of 85-90 mph, the throttles were opened with propellers set to fine pitch, but the port engine did not respond. As altitude decreased, the landing gear lever was moved to the up position and the port propeller was feathered. The airspeed indicator fell to 70-80 mph. Flaps were raised to 20°, and the aircraft sank and yawed left. Shortly after clearing some trees, the aircraft stalled and impacted the ground with the starboard engine at full power.
Investigation Findings
The probable cause of the accident was a failure of the port engine. Specifically, the vibration damper bolt had partially unscrewed from the roller, allowing the rear damper ring to operate on the bolt shank, which eventually failed under excessive loading.