Incident Details
A helicopter pilot reported that during startup on an off-airport landing pad, the aircraft was facing into the wind and the airspeed indicator displayed gusting wind conditions. As the blades began to rotate, the pilot felt a strong gust of wind and simultaneously heard a loud bang. The helicopter then lurched approximately 5 degrees to the right. The pilot immediately aborted the start procedure and applied the rotor brake.
Post-Accident Examination
An examination conducted after the incident revealed that the helicopter's main rotor blade had struck the tail rotor driveshaft cover. This impact damaged the tail rotor drive shaft and its support assembly. The pilot reported that there were no preaccident mechanical failures or malfunctions with the helicopter that would have precluded normal operation.
Weather Conditions
According to the pilot, the weather at the accident site around the time of the incident was wind from 130° at 25 knots, gusting to 30 knots, with light terrain-induced turbulence.
Flight Manual Information
The helicopter's flight manual states that the wind envelope for spinning and stopping the rotors has been substantiated for winds of 40 knots from any direction and for 50 knots headwinds.