The Director of National Parks did not actively manage the risk of the aerial culling task being conducted in the Kakadu National Park, or effectively supervise the operation. As a result, an increase in the number of crew, a change in helicopter type and change of helicopter operator all progressed without requisite risk management. This exposed crew to avoidable harm during low-level aerial shooting operations.
Although the Director of National Parks’ safe operating procedures required shooters and spotters to wear helmets during aerial culling tasks, helmets were not provided or used on a routine basis.
Annex 6 to the Convention of International Civil Aviation did not mandate the fitment of flight recorders for passenger-carrying aircraft under 5,700 kg. Consequently, the determination of factors that influenced this accident, and numerous other accidents have been hampered by a lack of recorded data pertaining to the flight. This has likely resulted in important safety issues not being identified, which may remain a hazard to current and future passenger carrying operations.
The ATSB is issuing the following recommendation:
There was no regulatory requirement from the Civil Aviation Safety Authority for piston‑engine aircraft to carry a carbon monoxide detector with an active warning to alert pilots to the presence of elevated levels of carbon monoxide in the cabin.
Australian civil aviation regulations did not mandate the fitment of flight recorders for passenger-carrying aircraft under 5,700 kg. Consequently, the determination of factors that influenced this accident, and other accidents have been hampered by a lack of recorded data pertaining to the flight. This has likely resulted in the non‑identification of safety issues, which continue to present a hazard to current and future passenger-carrying operations.
Response by the Civil Aviation Safety Authority
Although detectors were not required to be fitted to their aircraft, Sydney Seaplanes had no mechanism for monitoring the serviceability of the carbon monoxide detectors.
While the manufacturer's instructions for the zonal inspections detailed that installation blankets could be removed 'as necessary', they did not reference the insulation blanket installation procedure. This resulted in insulation blankets not being secured to the structure.
Pratt & Whitney Canada (PWC) PT6A-114A engines fitted with compressor turbine vane rings that have been repaired in accordance with the United States Federal Aviation Administration‑approved scheme STI 72-50-254 have a significantly increased likelihood of CMSX-6 compressor turbine blade fracture and subsequent failure of the engine compared to those engines fitted with PWC‑manufactured compressor turbine vane rings.
Virgin Australia Airlines did not require flight crew to confirm and verbalise external cues such as runway signs, markings, and lights to verify an aircraft’s position was correct prior to entering and lining up on the runway.
Virgin Australia Airlines did not require ATR flight crews to complete the Before take-off procedure prior to reporting ‘ready’ to air traffic control. This increased the risk of flight crews completing this procedure while entering the runway, diverting their attention to checklist items at a time when monitoring and verifying was critical.
The Robinson R44 pilot’s operating handbook low rotor RPM recovery procedure did not include reference to the minimum power airspeed for the helicopter as a consideration, which may assist a pilot to recover from a low rotor RPM condition. [Safety Issue]
Professional Helicopter Services did not have a calibration schedule for their passenger scales, which were under-reading. This increased the risk of their helicopters not achieving their expected take-off performance.
Airservices Australia’s configuration of the integrated tower automation suite (INTAS) at Perth Airport had resulted in a situation where controllers performing some combined roles had the INTAS aural and visual alerts inhibited at their workstation. As a result, controllers performing such combined roles would not receive a stop bar violation alert or runway incursion alert at their workstation.
The location and design of taxiway J2 at Perth Airport significantly increased the risk of a runway incursion on runway 06/24 for aircraft landing on runway 03. Taxiway J2 was published as the preferred exit taxiway for jet aircraft and, although mitigation controls were in place, they were not sufficient to effectively reduce the risk of a runway incursion.
Although Qantas provided detailed guidance to flight crews about the content of departure and approach briefings, it did not specifically require aerodrome hot spots to be briefed.
The procedures in the aircraft maintenance manual relating to chip detector debris analysis were written in a way that could cause confusion and error. This probably influenced the actions of the maintenance personnel to release the aircraft to service with a deteriorating bearing.
The power turbine shaft in Pratt & Whitney Canada PW100 series engines operating in certain marine environments is susceptible to corrosion pitting, which can grow undetected between scheduled inspections. This increases the risk of shaft fracture resulting in engine failure.
The visual flight rules permitted balloons to arrive and depart in foggy conditions without assurance that sufficient visibility existed to see and avoid obstacles.
Cloncurry Air Maintenance had adopted a number of practices, which included using abbreviated inspection checklists, not recording all flight control disturbances and not progressively certifying for every inspection item as the work was completed, which increased the risk of memory-related errors and the omission of tasks.
The scheduled inspections recommended by Rolls-Royce to detect cracking in Trent 700 fan blades, were insufficient to detect early onset fatigue cracks in the membrane to panel bond before those cracks could progress to failure.