What happened
During cruise flight, the pilot determined that the helicopter's engine appeared to be malfunctioning. Acting on this assessment, he initiated a precautionary landing. However, directional control was not maintained during the descent and touchdown. This loss of control resulted in a hard landing, which subsequently caused the main rotor blades to strike the tail boom.
The investigation
An on-scene inspection was conducted immediately following the incident. The examination did not reveal any evidence of mechanical malfunctions or anomalies with the helicopter's systems prior to the event.
Findings
The primary contributing factor to the damage was the loss of directional control during the landing phase. The pilot's initial assessment of an engine malfunction led to a precautionary landing, but the subsequent handling of the aircraft resulted in structural contact between the rotor system and the tail boom.