The train was loaded by approximately 10 per cent more than that recorded on the consist, it is probable that the additional mass placed an extra load on the braking system and affected the handling characteristics of the train.
Although CHC Helicopter Australia’s operations manual stated that emergency medical service flights should be conducted under instrument flight rules (IFR) ‘where practical’, its procedures for night visual flight rules (NVFR) operations using night vision goggles did not clearly state when IFR rather than NVFR should be used.
Although the operator had procedures for conducting a verbal safety briefing prior to flight and had safety briefing cards available, its risk controls did not provide assurance that all passengers would understand the required procedures for emergency landings. More specifically:
The Bureau of Meteorology did not have a procedure to ensure that a recording of the local weather forecast for balloon operations in the Melbourne area was correctly uploaded and accessible to balloon pilots.
The general condition of the rail on the west track, in the vicinity of the rail fracture, contributed to relatively frequent failures in that area.
The engine manufacturer did not have specific inspection procedures in the maintenance documents of the propeller shaft to detect a fatigue crack originating from the dowel pin hole.
Civil Aviation Order 20.7.1B stipulated that a 1.15 (15 per cent) safety margin was to be applied to the actual landing distance for jet-engine aircraft with a maximum take-off weight greater than 5,700 kg. This safety margin may be inadequate under certain runway conditions, which increases the risk of a runway excursion. The corresponding guidance in Civil Aviation Advisory Publication 235-5(0) had not been updated to account for this.
Virgin Australia Airlines/Virgin Australia International did not have a policy requiring crews to independently cross-check environmental information and landing performance calculations in-flight, removing an opportunity to detect crew errors.
There was no regulatory direction from the Civil Aviation Safety Authority on how a damp runway was to be considered for aircraft landing performance.
Several months prior to the incident, Virgin Australia Airlines/Virgin Australia International changed their policy on calculating landing performance for damp runways from referencing a wet runway to a dry runway.
The hazard associated with the inability to separate aircraft that are below the appropriate lowest safe altitude at night was identified but not adequately mitigated. This resulted in a situation where, in the event of a simultaneous go-around at night during land and hold short operations at Melbourne Airport, there was no safe option available to air traffic controllers to establish a separation standard when aircraft were below minimum vector altitude.
The current legislation does not require commercial operators of aircraft not greater than 5,700 kg maximum take-off weight to provide instructions and procedures for crosschecking the quantity of fuel on board before and/or during flight. This increases the risk that operators in this category will not implement effective fuel policies and training to prevent fuel exhaustion events.
The presence of the earlier design of yoke on wagon NGKF 35898X was not detected during preventative maintenance activities.
The processes for monitoring the condition of the brushless exciter units’ electrical insulation were ineffective in detecting deterioration prior to unit failure.
The functionality of the Digital Train Radio System (DTRS) did not allow an emergency call to override an initial lower-priority call.
There was no network standard that directly dealt with increased derailment risk on small-radius curves.
Track geometry through the Rushall curve was not managed in accordance with Metro Trains Melbourne (MTM) network standards. A wide-gauge ‘A’ fault was not rectified in the field despite being closed-out on the asset management system.
The network’s track geometry standard did not include any specific requirement to limit a localised lateral angular discontinuity in rail line at a mechanical joint.
The network’s track geometry standards were probably unsuitable for small-radius Broad-Gauge curves. A combination of track geometry irregularities had increased the probability of flange-climb at several locations on the small-radius Rushall curve.
The positioning of the rail lubricators at this and several other locations on the network was not consistent with Metro Trains Melbourne (MTM) guidelines and probably reduced their effectiveness.
