Section 4 of Civil Aviation Advisory Publication (CAAP) 5.23-2(0), Multi engine Aeroplane Operations and Training of July 2007 did not contain sufficient guidance material to support the flight standard in Appendix A subsection 1.2 of the CAAP relating to Engine Failure in the Cruise.
Wear of the interlocking shrouds of the intermediate-pressure turbine blades had the potential to reduce the dampening effects of the feature, and may have led to the development of conditions suitable for fatigue cracking of the IP turbine blades.
The inconsistent application of the operator’s safety management system to the identification and rectification of database anomalies, and intermittent notification of these anomalies to crews increased the risk of inadvertent flight crew non compliance with published instrument approach procedures.
The operator’s lack of awareness of the data providers’ assumption that the operator was complying with DO-200A Standards for Processing Aeronautical Data, which was not mandated in Australia, meant that the quality of the data was not assured.
The operator had limited controls in place to manage the fatigue risk associated with early starts.
Paint application to the main rotor gearbox, gear carrier did not effectively protect the part from corrosion resulting from gearbox water ingress.
Differences in the traffic alert phraseology between the Manual of Air Traffic Services and Aeronautical Information Publication increased the risk of non-standard advice being provided by the controller to the pilot of the G-IV during the compromised separation recovery.
The aircraft's centre of gravity varied significantly with hopper weight and could exceed both the forward and aft limits at different times during a flight.
The Auto Release procedures at Melbourne Airport allowed for aircraft to be departed at or close to the separation minima, with no controls in place to ensure aircraft would maintain a minimum speed and flight crews would advise air traffic control if the speed could not be achieved.
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.
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.
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.
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 Williamtown air traffic control procedures did not clearly define the separation responsibilities and coordination requirements between the Approach sectors for departing aircraft.
The Department of Defence’s air traffic controllers had not received training in compromised separation recovery techniques.
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 presentation on the aircraft load sheet of the zero fuel weight immediately below the operating weight, increased the risk of selecting the inapropriate figure for flight management system data entry.
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.
