Accident Sequence
A pilot was conducting local pattern practice maneuvers. After completing a quick stop and hovering, another takeoff was initiated. The pilot reported that an unusual amount of forward cyclic was required to begin forward flight. During the final approach, full forward cyclic was not sufficient to maintain forward flight. The aircraft stopped short of the intended landing spot and began moving backward. The pilot attempted to recover, during which the aircraft struck the ground.
Examination Findings
The broken support assembly for the fore and aft cyclic control, part number 47-724-132-1, was examined. It was found to be a very poor quality casting. Cold shuts and shrinkage cavities were observed on approximately 70% of the fracture surface.
Conclusion
It was concluded that the fore and aft cyclic control failed by a slow fracture process initiated by the presence of large casting defects.