The Australian Transport Safety Bureau (ATSB) is asking for pilots, operators, and engineers with knowledge of aft tail cone bulkhead or tail rotor gearbox input cartridge damage involving Robinson R22, R44 and R66 helicopters to make contact.
The call for information comes as the ATSB releases an investigation update from its ongoing investigation of a fatal Robinson R44 helicopter accident in Broome, Western Australia on 4 July 2020.
During the accident flight, the R44’s tail rotor gearbox, tail rotor and tail assembly separated from the helicopter soon after take-off. The helicopter subsequently collided with the ground, fatally injuring the pilot and rear-right passenger, while the other two passengers sustained serious injuries.
The ATSB has since undertaken extensive and ongoing metallurgical examination and analysis of the airframe and tail rotor components, including examining other R44 helicopter tail rotor gearboxes, components and bulkhead castings.
“Due to the disruptive nature of the accident, this examination and analysis may not reveal a specific point of failure in the helicopter,” said ATSB Director Transport Safety Dr Mike Walker.
“Indeed, in similar accidents overseas, despite extensive materials analysis, contributing factors have not been identified.”
Dr Walker said the ATSB has to date worked closely with the manufacturer, the US National Transportation Safety Board and the UK Air Accidents Investigations Branch to better understand this and similar accidents involving the R44 helicopter, and was now seeking the assistance of industry.
“To help us better understand the nature of this accident, we are seeking Robinson R22, R44 and R66 helicopter pilots, operators and maintenance engineers who may have knowledge of aft tail cone bulkhead or tail rotor gearbox input cartridge damage to make contact with us as soon as practical,” he said.
Regulations under the Transport Safety Investigation Act 2003 require the ATSB to be notified of damage sustained from when an aircraft is being prepared for flight until it has landed and passengers and crew have disembarked, but not for damage sustained during ground handling.
“There may have been events during ground handling resulting in damage to Robinson helicopters that were not required to be reported to the ATSB,” said Dr Walker.
“As a result, industry may be aware of information that could significantly aid the ATSB’s investigation.”
Any information provided to the ATSB that could assist the investigation would be protected as evidence under the Transport Safety Investigation Act 2003, Dr Walker noted.
“If damaged components are available, we may seek to recover these for examination,” he said.
The context of the occurrence and the results of ATSB’s analysis will be published in the final report at the conclusion of the investigation.
"At this point in the investigation it is important to stress that the ATSB has not determined that this helicopter sustained ground handling damage, nor that damage while ground handling contributed to this accident," Dr Walker stated.Last update 17 August 2021