Primary finding
Probable cause
The pilot’s failure to maintain clearance from terrain while maneuvering at a low altitude.
Investigator assessment
Analysis narrative
The pilot reported that, he was using a helicopter to drive horses and misjudged his height above the terrain when a horse unexpectedly turned toward him. He pulled back on the cyclic, the tail rotor struck the terrain, and the helicopter immediately started a yaw to the right. The pilot rolled the throttle off to slow the turn and cushioned the landing by adding collective. Once outside the helicopter the pilot noticed that the tail rotor driveshaft had sustained substantial damage. The pilot reported that there were no preaccident mechanical failures or malfunctions with the helicopter that would have precluded normal operation.