Primary finding
Probable cause
The pilot’s failure to maintain rotor rpm while maneuvering at low altitude with low airspeed and a tailwind.
Investigator assessment
Analysis narrative
According to the helicopter pilot, during an agricultural flight, he made a downwind turn to spray the intended field. During the low airspeed right turn, he increased the engine power, and the rotor rpm decreased. He reported that he leveled the helicopter to clear power lines, but the rotor rpm remained low. The helicopter descended, and the pilot landed the helicopter in a corn field. The helicopter sustained substantial damage to the tailboom and horizontal stabilizer. The nearest METAR located 15 nautical miles south-southeast from the accident site reported that, about the time of the accident, the wind was calm. The pilot reported that there were no preaccident mechanical malfunctions or failures with the helicopter that would have precluded normal operation.
Source record
Factual narrative
According to the helicopter pilot, during an agricultural flight, he made a downwind turn to spray the intended field. During the low airspeed right turn, he increased the engine power and the rotor RPM decreased. He reported that he leveled the helicopter to clear powerline wires, but the rotor RPM remained low. The helicopter descended, and the pilot landed the helicopter in a corn field. The helicopter sustained substantial damage to the tailboom and the horizontal stabilizer. The nearest METAR was 15 nautical miles south-southeast and reported that about the time of the accident, the wind was calm. The pilot reported that there were no preaccident mechanical malfunctions or failures with the helicopter that would have precluded normal operation.