Robinson Helicopter Company R44 II N178DF accident near Dustin, Oklahoma

Probable cause

The pilot’s insufficient monitoring of the helicopter’s power while flying at low altitude and at low airspeed, which resulted in the loss of rotor rpm and impact with a tree and terrain.

NTSB analysis

The pilot of the helicopter stated that, while maneuvering “low and slow” with three passengers onboard, he noticed “insufficient power” and shortly thereafter, the low rotor rpm warning annunciated. He applied full throttle and attempted to regain rotor rpm but was unsuccessful. The pilot stated that he was forced to land immediately, during which the helicopter impacted a tree then terrain, resulting in substantial damage.

The pilot reported that there were no mechanical malfunctions or failures of the helicopter and recommended operating “at a lower gross weight.” Postacccident examination of the helicopter revealed no anomalies that would have precluded normal operation.

Text from the NTSB. Open the NTSB docket for CEN21LA173 for the full record.