Primary finding
Probable cause
The pilot inadvertently allowing the helicopter to enter into a vortex ring state (settling with power) condition while he was lowering a long-line load to the ground, resulting in the helicopter settling to the ground and its tail rotor impacting part of the rigging used to haul the load. Factors include the long-line load and its rigging sitting on the ground at the point where the helicopter settled to the terrain.
Investigator assessment
Analysis narrative
The pilot, who was approaching an area where he was going to place a long-line load onto the terrain, inadvertently allowed the helicopter to enter into a vortex ring state (settling with power) condition, resulting in his inability to keep the helicopter from descending at a rate that resulted in it hitting the ground and bouncing back into the air. At the point in time when it contacted the ground with its skids, the helicopter's tail rotor impacted a portion of the rigging for the load that it had been hauling, which resulted in substantial damage to the tail rotor and the tail rotor drive shaft.
Source record
Factual narrative
The pilot, who was approaching an area where he was going to place a long-line load onto the terrain, inadvertently allowed the helicopter to enter into a vortex ring state (settling with power) condition, resulting in his inability to keep the helicopter from descending at a rate that resulted in it hitting the ground and bouncing back into the air. At the point in time when it contacted the ground with its skids, the helicopter's tail rotor impacted a portion of the rigging for the load that it had been hauling, which resulted in substantial damage to the tail rotor and the tail rotor drive shaft.