What happened
The pilot initiated an approach to a grass field for landing. As he applied power to flare the aircraft for touchdown, he was unable to arrest the descent rate effectively. This resulted in a hard landing impact with the ground.
During the impact, the main rotor blades struck the rear section of the aircraft, cutting the tail boom off from the helicopter fuselage.
The investigation
Following the accident, the Federal Aviation Administration (FAA) conducted an examination of the helicopter to determine if mechanical issues contributed to the event. The post-accident inspection failed to find any evidence of a mechanical failure or malfunction in the aircraft systems prior to the impact.
Findings
The primary factor leading to the damage was the hard landing caused by the pilot's inability to stop the descent during the flare phase. The structural failure of the tail boom was a direct result of the rotor blades contacting it upon impact with the ground, not due to pre-existing mechanical defects.