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The Australian Transport Safety Bureau has released an update from its on-going investigation into the fatal accident involving a Robinson R44 helicopter at Broome, Western Australia on 4 July.
"Based on CCTV footage and examination of the wreckage, ATSB investigators have been able to determine that the helicopter's tail rotor gearbox, tail rotor and tail assembly separated from the helicopter soon after take-off," said ATSB Chief Commissioner Greg Hood.
Following the in-flight separation of the tail, the helicopter then fell to the ground, out of control.
"We appreciate that this information may be confronting to the families and friends affected by this tragic accident, and it is for this reason that the ATSB will not be releasing the CCTV footage due to its potentially distressing nature," Mr Hood said.
Since arriving on site in Broome on Monday, transport safety investigators have conducted a detailed inspection of the helicopter wreckage, and are arranging to transport relevant components back to the ATSB's technical facilities in Canberra for further examination.
Investigators have also interviewed a pilot who flew the accident aircraft on 2 July who reported feeling unusual vibrations through the tail rotor pedals. The pilot of the accident flight also conducted a short flight in the helicopter and confirmed the unusual vibrations.
Maintenance personnel subsequently conducted a dynamic tail rotor balance on the day before the accident.
"At this stage the reasons for the in-flight breakup, and the significance of the reported vibrations through the tail rotor pedals, are not known, and the ATSB will provide further advice when relevant information is available," Mr Hood said.
"While the investigation is on-going, the ATSB urges any R44 pilot that experiences unusual vibrations through the tail rotor pedals to land as soon as possible."
As the investigation progresses, the ATSB will continue to liaise with the Civil Aviation Safety Authority, the US National Transportation Safety Board, and the Robinson Helicopter Company.
The Robinson R44 was certified in December 1992 and the model involved in this accident, the R44 Raven I, was introduced in January 2000. There are currently 558 R44s on the Australian civil aircraft register.
You can find here the update AO-2020-033: In-flight breakup involving Robinson R44 Raven I, VH-NBY, 2 km north of Broome Airport, Western Australia, on 4 July 2020
