Incident Overview
A helicopter in cruise flight over rough, uneven terrain experienced a partial loss of engine power. The pilot executed an autorotation landing in a corn field. According to the pilot's statement, due to the uneven terrain, he made the decision to reduce airspeed to zero during touchdown. He reported leveling the helicopter and pulling collective to cushion the landing. During the landing, a main rotor blade separated the tail boom from the fuselage.
Examination Findings
An examination of the helicopter did not disclose evidence of mechanical malfunction. No pre-existing mechanical issues were identified that could have contributed to the partial power loss or the subsequent blade strike.
Pilot Actions
The pilot's decision to zero out airspeed during touchdown and the use of collective pitch to soften the landing were noted. The separation of the tail boom occurred as a result of the main rotor blade contact during the landing sequence.