Fatal Crash Broome 4th July 2020

[Cloudee]

Have a look at the standard of aircraft operation in the Wild North West of Western Australia.

Contributing factors

• Following a period of pedal vibration over at least 2 flights, overstress fracture of the attachment lugs of the tail rotor gearbox input cartridge occurred. The source of the loading that led to the overstress fracture was not conclusively determined.
• Two pilots experienced vibration through the helicopter’s tail rotor pedals on separate flights and did not endorse the problem on VH-NBY’s maintenance release. Additionally, following tail rotor inspection and vibration analysis on the ground, the engineers did not endorse the requirement for a maintenance check flight on the maintenance release. As a result, the value of the maintenance release as a tool for communication and management of airworthiness was lost.
• A recommendation in the R44 pilot's operating handbook was not followed. It advised pilots that following detection and inspection of an unusual vibration, they should hover the helicopter then have it reinspected before resuming free flight.
• The pilot conducted a towering high-power take-off in VH-NBY from a confined area with 3 passengers on board. The unnecessary carriage of passengers resulted in a significantly more severe outcome following the inflight breakup.
• Shortly after take-off, following the overstress fracture of the attachment lugs, the tail rotor gearbox separated from the helicopter. This led to fracture of the aft tail cone bulkhead and separation of all components attached to it, including the horizontal and vertical stabilisers.
• With limited time and the stress associated with the emergency event, the pilot did not apply the pilot’s operating handbook procedure for responding to a tail rotor emergency. Prompt application of the procedure would have reduced the likelihood of loss of control, and therefore improved the potential for survivability.

Other factors that increased risk

• The pilot did not have a valid flight review for the R44 helicopter type or a current medical certificate. The former increased the risk of an inappropriate response to the tail rotor emergency and the pilot was not legally authorised to operate an R44 helicopter at the time of the accident.
• The owner of VH-NBY demonstrated acts of non-compliance with multiple aviation safety regulations. Additionally, VH-NBY was operated in a manner that increased the risk of damage or stress to the helicopter on multiple occasions. These actions had an adverse influence on safety and imposed unnecessary risk on passengers and third parties.
• Although the registered operator of VH-NBY was responsible for the continued airworthiness of its helicopter fleet, they did not employ a conservative defect resolution process that would have supported further trouble shooting.

Other findings

• The attending engineers found that visual inspection of the tail rotor system and associated components, running the helicopter on the ground, and dynamic tail rotor balancing, could not replicate the stated problem. It is likely that the vibration only presented in powered flight.
• There was a history of unreported accidents and incidents with the registered operator of VH‑NBY's aircraft, in both commercial and private operations. These occurrences included 2 tail rotor strikes in different R44 helicopters, and a total hull loss of another R44 helicopter (VH‑ZGY) that resulted in serious injuries to a passenger.
• Although a fuel bladder was punctured during the accident sequence, and fuel was lost from the tanks, the fuel bladders reduced the flow rate of escaping fuel, which reduced the risk of a post-crash fire.