Incident Overview
Shortly after takeoff, the aircrew heard a loud noise and observed sparks coming from the right side of the right engine. They attempted to feather the right engine, but it would not respond. Unable to maintain altitude, the aircraft descended into trees. After striking the trees, the aircraft came to rest on the roof of a house. Approximately 5 to 10 minutes after the crash, the aircraft burst into flames. A police officer who had responded and climbed onto the roof was reportedly thrown off by an explosion, sustaining minor injuries.
Examination Findings
An examination of the right engine revealed that one blade of the model HC-82XG propeller did not feather and was free to move. The retaining clamp on this blade was cracked and had a portion missing. A metallurgical examination determined that the clamp had failed from high cycle fatigue. Hartzell Propeller Service Bulletin No. 126, dated December 9, 1980, recommended that this old model clamp be replaced by a new improved type. No other preimpact failures were found.