N4164T

On March 11, 2023, about 1530 central standard time, a Robinson Helicopter R-44, N4164T, was substantially damaged when it was involved in an accident near De Kalb, Texas. The pilot and one passenger were not injured, a second passenger sustained minor injuries, and a third passenger was seriously injured. The helicopter was operated as a Title 14 Code of Federal Regulations Part 91 aerial observation flight.

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.

The helicopter sustained damage to the fuselage, main rotor blades, and tail boom. The aft portion of the tail boom, with the tail rotor assembly attached, was separated from the remainder of the airframe. It was located adjacent to the fuselage at the accident site.

Postrecovery airframe and engine examinations, which included an 8-minute engine run, did not reveal any evidence of an in-flight structural failure, a flight control malfunction, or an inability of the engine to produce rated power. Although, the separated portion of the tail boom and tail rotor assembly were present at the accident site, they were not with the wreckage when recovered.

The postrecovery examinations were 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 low rotor warning indicator bulb illuminated, and the warning horn emitted an audible sound when electrical current was applied. The reason for the failure of the low rotor warning system was not determined.