Robinson Helicopter R44 N4164T accident near De Kalb, Texas

Probable cause

The pilot’s inability to maintain control of the helicopter due to his failure to maintain rotor speed. Contributing to the accident was the failure of the helicopter’s low rotor speed warning system.

NTSB analysis

The flight was conducted to hunt feral hogs. The pilot reported that a group of hogs had entered a large field, and he lowered the collective to maneuver the helicopter closer. When he lowered the collective, he perceived a loss of engine and rotor speed. The helicopter immediately began to lose lift. Once the pilot realized that he could not recover the helicopter, he attempted a running (skid-on) landing. However, the landing skids got stuck in the muddy field, the helicopter rocked forward, and the main rotor blades struck the ground causing the aircraft to roll over.

The pilot reported the low rotor speed warning did not activate when the rotor speed started to decay. He also stated that all required preflight checklists were complied with before the flight began and no anomalies were noted.

A postrecovery examination was unremarkable with exception of the low rotor warning system, which was not operational at the time of the examination. Specifically, the warning system did not activate when the collective control was brought off the low pitch stop and increased to full travel. The reason for the failure of the low rotor warning system was not determined.

Text from the NTSB. Open the NTSB docket for CEN23LA130 for the full record.