The Virgin Australia 737-800 that diverted to Mildura last month was put down by the pilots without certainty as to their position along its runway,  and came to a halt with almost no fuel left in its tanks.

The details about that flight, and a Qantas 737-800 that had also diverted to Mildura are disclosed in a preliminary report by the ATSB today. (Download and study the report, not the press release.)

Passengers on the Virgin flight, which started in Brisbane as an Adelaide service, were ordered to BRACE, BRACE, BRACE by cabin crew as their jet, with no option left but to touch down, landed in a blinding fog and had only 535 kilograms of fuel left in its tanks upon engine shutdown.

By contrast, the Qantas 737-800 flight, which had departed Sydney for Adelaide, had 2100 kilograms of fuel left after it landed in poor visibility on its first attempt.

The Virgin Australia flight, which had intended to land before the Qantas flight, had deferred to the Qantas flight after a radio communication between the jets caused the Virgin captain to conclude that the Qantas flight was  lower in fuel than it was, and invited it to land first, and possibly provide it with advice about the visual conditions it experienced close to the ground.

Subsequently the Virgin flight made one missed approach to the runway and was left with no alternative but to land on its second approach.

This act of courtesy by the Virgin Australia pilots could be seen as helping bring it closer to disaster.

ATSB diagram of two 737 positions before Mildura diversions

The factual sequence of events disclosed by an interim ATSB report into the incident show just how badly safety can be affected by an Australian rule that allows airliners to fly between cities without fuel for an alternative airport.

The lightly loaded Virgin jet (91 passengers and crew) and the nearly full Qantas 737 (152 on board) were both headed for Adelaide on the morning of 18 June without any alternative airport flight planning, because Australia allows passenger airliners to take off without what is considered a fundamental requirement for safe operations in most of the world.

The ATSB says the focus of its final report into these events, due next June, will include close examination of the quality of the weather information given to both flights, as well as the information given to their respective flight crews by their airlines.

[It would be very surprising, and wrong, for both airlines to wait until the final report comes out before taking steps to ensure that nothing like the events of 18 June are ever again allowed to put their passengers and their brands at such risk as seen that morning, when poor weather information, inadequate air safety rules relating to alternative airports, and in one case, a failure to keep crew up to date with changed route circumstances, all lined up to create a seriously dangerous situation.]

The Qantas flight was given timely weather updates by the company. The Virgin Australia flight was left ignorant of the changed circumstances that lead to fog diversions at Adelaide airport until they were drawn to its attention by air traffic control.

This extract from the detailed report comes within the ‘white knuckle’ category of aviation safety incident literature.

The [Virgin Australia] aircraft left controlled airspace en route to Mildura and, on first contact with the sector controller with responsibility for that airspace, the crew were provided with the expected traffic at Mildura for their ETA of 0832 (local time). This included: a Saab 340 aircraft that was expected to arrive 2 minutes prior to YIR [the Virgin Australia 737]; a De Havilland DHC-8 aircraft, arriving 2 minutes after YIR’s ETA and another Saab 340 aircraft arriving 6 minutes later; and VYK [ the Qantas 737] with an ETA of 0842.As they descended through about 10,000 ft in visual conditions, it became obvious to the crew of YIR that the weather conditions were not as reported and that there appeared to be fog at Mildura and low cloud in the area. An indication of the actual weather at Mildura was not possible from the automated weather information service (AWIS)[1] at the airport as it was unavailable. This unavailability was published via NOTAM. The crew were anticipating a low fuel warning at approximately 2,000 kg fuel remaining, and decided to action the relevant checklist.

As they approached the airport, it became even clearer that the weather was worse than reported and they heard the crew of the Saab 340 aircraft report conducting a missed approach and diverting to Broken Hill.

The crew elected to discontinue the visual approach, and activated the RNAV(GNSS) approach previously loaded into the flight management system. They decided to commence the approach from waypoint MIAEC, which was located to the south-east of the airport. At the same time, they heard the crew of one of the DHC-8 aircraft report that they were tracking to a waypoint located to the east of the airport to commence the RNAV(GNSS) approach. The crew of YIR reported that, in response, they turned to the right slightly to increase the distance between themselves and that aircraft and that they were in visual flight conditions at that time, above the low cloud and fog.

As the crew turned and tracked to MIAEC to commence the approach, they reported hearing the crew of VYK also tracking direct to MIAEC and asking the crew of YIR for their intentions. The crew of YIR advised that they were commencing an approach via MIAEC. The crew of VYK replied that they were also commencing the approach and that fuel was an issue. The crew of YIR reviewed their fuel status and, assessing the intent of the radio transmission from the crew of VYK as meaning that they had less fuel than YIR, elected to fly to the north of MIAEC and allow the crew of VYK to conduct their approach first. They visually sighted VYK and reported that they were well clear, continuing to monitor VYK’s position via their aircraft’s traffic collision and avoidance system (TCAS).

The crew of YIR also decided that if VYK conducted the approach first, the crew of that aircraft would then be able to give them an appreciation of the weather and actual cloud base at Mildura. A DHC-8 aircraft reported going around and diverting due to fog as the crew of YIR monitored the progress of VYK on TCAS and discussed their own approach.

The crew of VYK conducted the RNAV runway 27 approach and landed (see the following section titled VH‑VYK arrival at Mildura for further information). Following that landing the crew of VYK advised the crew of YIR that they had become visual approximately 150 ft below the minimum descent altitude[2] and that visibility was around 3,000 m.

At approximately 0858, the crew of YIR commenced their first approach, deciding that if they obtained visual reference with the runway, they would land and that if they were not visual they would conduct a missed approach. The crew of YIR had planned to descend to a minimum of 300 ft[3], and configured the aircraft early for the final approach. They reported entering the fog layer at about 800 ft. The PIC concentrated on flying the aircraft, while the FO provided support and assessed the aircraft’s position visually over the ground. The FO indicated that visibility to the front of the aircraft was virtually non-existent, so he elected to look down from the right cockpit side-window to assess their position. He recalled sighting the threshold as the PIC called going around. The FO provided support to the PIC and during the go around sighted the crossing runway.

As the aircraft climbed out, the crew became visual above the fog at approximately 800 ft and conducted a right circuit. They discussed the first approach and assessed that the RNAV (GNSS) approach would place them over the physical runway environment successfully. Due to their fuel state, they were required to land from the next approach, regardless of conditions.

The crew briefed the cabin crew of their plan and that they would be given an emergency landing call during the approach and should review their actions and prepare the cabin accordingly. The cabin crew asked when they should commence their actions and the crew indicated that there would be a public address (PA) announcement during the final approach. The crew also indicated that the touchdown would be firm and that they had about 4 minutes before landing.

As the crew reconfigured the aircraft for the second approach, they decided to raise the height of their seats to improve the downward visibility ahead of the aircraft. The PIC also reported assessing the wind velocity from the navigation display during the base leg and from that assessed where the runway was likely to be in relation to the cockpit windows during the landing. The FO decided that it would be best to allow the PIC to concentrate on flying the aircraft and that he would make the PA broadcast to the cabin for the PIC. He recalled making the appropriate radio calls and hearing the second DHC-8 aircraft holding overhead Mildura at 10,000 ft.

The flight crew commenced the final approach and the FO made the ‘BRACE BRACE BRACE’ PA announcement as the aircraft passed 600 ft. The cabin crew immediately called for passengers to keep their heads down.

The FO then looked outside and down to obtain visual reference with the ground and saw the same visual features as he had on the first approach. He assessed the aircraft was over the runway and reported hearing the PIC disconnect the autopilot. The crew could not determine where they were in relation to the length of the runway and flew the aircraft onto the ground. The crew recalled hearing an enhanced ground proximity warning system (EGPWS) sink rate warning and that the touchdown was ‘firm’. The crew obtained slightly better visual cues as the aircraft rolled out on the runway and conducted the normal after touchdown and rollout procedures. As the aircraft was turned off the runway, the FO made a PA to the cabin advising that they had landed and that the emergency procedures were no longer applicable.

The crew taxied to the parking area and shut down the aircraft at 0918. The recorded total fuel remaining in the fuel tanks on shut down was 535 kg.

[1]      The aerodrome weather information service (AWIS) provides actual weather conditions, via telephone or radio broadcast, from Bureau of Meteorology automatic weather stations.

[2]      The minimum descent altitude for the runway 27 RNAV(GNSS) approach is 660 ft AMSL. This equates to 493 ft above the ground.

[3]      The elevation of Mildura is 167 ft. A minimum of 300 ft would place the aircraft approximately 150 ft above ground level.

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