What happened
Shortly after liftoff from a privately owned airstrip, the helicopter's engine experienced an overspeed condition. In response to the mechanical failure, the pilot initiated an autorotation maneuver to land in an adjacent open field.
During the descent, the pilot misjudged the flare altitude. The aircraft impacted the ground with significant force, causing the main rotor blades to sever the tailboom assembly. Following the impact, the helicopter rolled over onto its left side as the forward left skid dug into the soft terrain.
The investigation
The source text does not provide specific details regarding a mechanical examination or findings beyond the initial engine overspeed event and the resulting structural damage.