Helicopter Tail Rotor Drive Shaft Failure Leads to Autorotation Landing (N13CM)

What happened

The pilot was operating a helicopter when the aircraft experienced an uncommanded rotation to the right while maintaining a twenty-degree left bank and an airspeed of approximately forty knots. In response to this loss of directional control, the pilot initiated an autorotation maneuver. The helicopter touched down with a forward speed of about five knots.

The investigation

A post-accident examination of the aircraft revealed that the tail rotor drive shaft had failed during operation. Maintenance records indicated that the failed component had accumulated approximately 1314 flight hours prior to the incident.

Findings

The failure of the tail rotor drive shaft was the primary mechanical issue identified. The pilot's decision to enter autorotation allowed for a controlled landing despite the loss of anti-torque capability.