Tail Rotor Push Pull Tube Was Found Bent And Severed Aft Of The Tail Rotor Gear Box Near The Bell Crank Assembly

Location: Honolulu, HI Accident Number: ANC24LA077
Date & Time: August 18, 2024, 16:00 Local Registration: N740RH
Aircraft: Robinson R44 Injuries: 1 None
Flight Conducted Under: Part 135: Air taxi & commuter - Non-scheduled - Sightseeing

On August 18, 2024, about 1600 Hawaii-Aleutian standard time, a Robinson R44 helicopter, N740RH sustained substantial damage when it was involved in a pre-take off accident near Honolulu, Hawaii. The pilot was uninjured. The helicopter was operated as a Title 14 Code of Federal Regulations Part 135 sightseeing flight.

The flight operated by Novictor Aviation, DBA Rainbow Helicopters, was preparing to depart on the fourth flightseeing tour of the day. The pilot stated she started the engine and engaged the main rotor clutch prior to boarding the passengers. As the main rotor system began to engage, she felt and saw the left pedal deflect full forward without any control input. The pilot immediately shut down the engine, stopped the rotors and exited the helicopter to inspect the tail rotor assembly. The tail rotor push pull tube was found bent and severed aft of the tail rotor gear box near the bell crank assembly.

A detailed post-accident examination revealed that the tail rotor push-pull tube fractured near the bell crank assembly of the tail rotor gearbox. Once the tail rotor gearbox was removed, it revealed a bolt missing from the flex coupling/yoke flange assembly just forward of the tail rotor gearbox. The bolt and nut were subsequently found inside the tail boom, near the tail rotor gearbox. Additionally, the severed tail rotor push-pull tube was found wrapped around the tail rotor drive shaft.

Additionally, corresponding witness marks on the damaged push-pull tube matched the circumference of the bolt found within the tail boom.

FMI: www.ntsb.gov