Accident Overview
A helicopter engaged in sling load logging operations experienced a tail rotor strike during climb-out. The pilot had just completed depositing the final log and was departing the logging area when the tail rotor assembly contacted a tree, causing it to detach from its attach bracket. The pilot subsequently executed an autorotation to manage the descent, and the helicopter made a hard landing upon touchdown.
Examination Findings
Metallurgical analysis of the helicopter's 90-degree gearbox revealed no indications of fatigue on the fractured surfaces. A comprehensive inspection of the wreckage found no evidence of any preexisting malfunctions or failures in the airframe or engine systems.
Sequence of Events
The flight was part of a series of sling load logging operations. After setting down the last log, the pilot began climbing out from the area. During this climb, the tail rotor assembly struck a tree and separated from its attachment point. The pilot reacted by initiating an autorotation, which is a procedure used to descend without engine power. The helicopter touched down firmly at the end of the autorotation.
Investigation Results
Investigators examined the fractured components of the tail rotor assembly and the 90-degree gearbox. The metallurgical examination did not identify any fatigue cracking on the surfaces of the fractured parts. Additionally, the overall wreckage examination did not uncover any preexisting issues with the airframe or engine that could have contributed to the event.