A significant number of R44 helicopters, including VH-HFH, were not fitted with bladder-type fuel tanks and the other modifications detailed in the manufacturer's service bulletin 78 that were designed to provide improved resistance to post-impact fuel leaks.
A number of self-locking nuts from other aircraft, of the same specification as that used to secure safety-critical fasteners in VH-HFH, were identified to have cracked due to hydrogen embrittlement.
Some ARTC maintenance contractors were using non-authorised reproductions of the ARTC’s Track Occupancy Authority form.
The ARTC form ANRF-002 (Track Occupancy Authority) was deficient as there was no provision to record critical information regarding the location and type of worksite. Consequently, both the Protection Officer and Network Control Officer incorrectly concluded that the train had passed beyond the limits of the worksite.
The track workers were not provided with sufficient training (competency based or structured on-job training) in relation to the hazards and required protections for working under the authority in place at Newbridge on 5 May 2010.
It was possible that at times throughout the Network Control Officer’s roster, fatigue levels were conducive to performance degradation.
The ARTC procedure ANPR-701 (Using a Track Occupancy Authority) was inconsistent in that it did not allow for a scenario that would otherwise be permitted, and intended, under rule ANWT-304 (Track Occupancy Authority).
High service time stage-2 LP turbine blades were susceptible to a reduction in fatigue endurance as a result of vibratory stresses sustained during operation at speeds close to the maximum.
LP turbine support bearings (part numbers LK30313 and UL29651) showed increased susceptibility to breakdown and collapse under vibratory stress conditions associated with LP turbine blade release.
The ship’s safety management system documentation provided the crew with no guidance in relation to the operation and maintenance of the ship’s oxygen breathing apparatus.
The threaded connections on the Kawasaki air breathing apparatus and oxygen breathing apparatus cylinders were the same and there were no other engineering controls to prevent an oxygen cylinder from being connected to the air compressor.
The ship’s crew were not appropriately trained or drilled in the operation and maintenance of the oxygen breathing apparatus.
New Section Closing and Opening Authority Telegrams (SCAO) were not completed by the train controller and the Supervisor (Track Machines) for each closing and opening of the track in accordance with WestNet Rule 199.
The Australian Transport Safety Bureau encourages all operators and owners of R44 helicopters that are fitted with all-aluminium fuel tanks to note the circumstances of this accident as detailed in this preliminary report. It is suggested that those operators and owners actively consider replacing these tanks with bladder-type fuel tanks as detailed in the manufacturer's Service Bulletin (SB) 78A as soon as possible.
The Department of Defence’s air traffic controllers had not received training in compromised separation recovery techniques.
The Williamtown air traffic control procedures did not clearly define the separation responsibilities and coordination requirements between the Approach sectors for departing aircraft.
An important alerting function within the Australian Defence Air Traffic System had been disabled at Williamtown to prevent nuisance alerts.
The aircraft operator’s flight crews were probably not adequately equipped to manage the vertical profile of non-precision approaches in other than autopilot managed mode.
The operators procedures did not include a validation check of the landing weight generated by the flight management system which resulted in lack of assurance that the approach and landing speeds were valid.
The operator's procedure for confirming the validity of the flight management system generated take-off weight did not place sufficient emphasis on the check against the load sheet.
