What happened
The private pilot was conducting solo flight operations to practice autorotations. The intended landing area was an open field characterized by unevenly sloped terrain. During the maneuver, the pilot allowed the main rotor revolutions per minute (RPM) to decrease significantly. Consequently, the pilot was unable to restore adequate rotor RPM prior to touchdown.
The helicopter impacted the ground with excessive vertical speed. This hard landing resulted in the collapse of the left skid within the landing gear system. Following the initial impact, the main rotor assembly continued its rotation and made contact with the tailboom structure.
The investigation
Examination of the aircraft revealed significant damage to the lower fuselage area. The left skid was found collapsed due to the forces generated during the hard landing. Additionally, the main rotor blades had sustained contact with the tailboom, indicating a loss of sufficient lift and control authority during the final phase of the autorotation.
Findings
The primary factor in this accident was the pilot's failure to maintain adequate rotor RPM during the practice maneuver. The uneven terrain may have contributed to the difficulty in judging altitude and airspeed accurately. fuel exhaustion is not the cause; rather, it was a loss of rotational energy essential for a safe flare and touchdown.
The aircraft type involved was a helicopter, though specific make and model details were not provided in the source text. No other individuals were injured or killed in this incident.