Primary finding
Probable cause
The pilot’s encounter of a downdraft from which there was insufficient altitude to recover.
Investigator assessment
Analysis narrative
The pilot reported that he had descended the helicopter to about 50ft above ground level along a ridgeline when he encountered a downdraft from an opposing ridgeline. He attempted to fly out of the downdraft by flying towards lower ground but did not have the power or airspeed to arrest the descent. The helicopter’s low rotor RPM came on as the helicopter impacted terrain and rolled onto its left side. The helicopter sustained substantial damage to the main rotor system, fuselage, and tail boom. The pilot reported that there were no preaccident mechanical malfunctions or failures with the helicopter that would have precluded normal operation.