Primary finding
Probable cause
The pilot's loss of helicopter control on approach to land due to entering a vortex ring state condition, which resulted in a hard landing.
Investigator assessment
Analysis narrative
The pilot in the helicopter reported that, he turned final approach at about 100 ft above ground level and the helicopter started settling with power [entered vortex ring state]. The pilot attempted to stop the descent by applying collective and forward cyclic, but the helicopter subsequently landed hard and sustained substantial damage to the aft fuselage. The pilot reported that there were no preaccident mechanical malfunctions or failures with the helicopter that would have precluded normal operation.