Created Thursday, Nov 12th 2020 11:18Z, last updated Thursday, Nov 12th 2020 11:18Z
A Virgin Australia Airlines Avions de Transport Regional ATR-72-212A, registration VH-FVR performing flight
VA-1174 from Sydney,NS to Albury,NS (Australia) with 66 passengers and 4 crew, was on a final RNAV Z approach to Albury's runway 25 descending through about 1400 feet MSL/600 feet AGL.
A private Piper PA-28 had been on a training flight and was contacting tower at about the same time the ATR contacted tower. The pilot was instructed by tower to join a right downwind and was subsequently provided with onward clearances for a touch and go. Immediately afterwards the ATR crew reported crossing the final approach fix. Tower advised the PA pilot he was number 2 for landing and was to follow the arriving ATR. However, the pilot did not see the ATR and did not notify tower that he could not see the ATR, but instead acknowledged the transmission with his callsign only (no readback of the information received), about 40 seconds later the pilot turned base and subsequently began to turn final when the crew of the ATR received a TCAS traffic advisory. The crew caught sight of the PA about 75 feet below and about 111 meters (0.06nm) away and immediately initiated a go around due to the close proximity.
The ATR climbed to safety, positioned for another approach and landed safely on second approach about 10 minutes later, the PA continued the final but went around due to being too fast and subsequently left the airspace of Albury.
On Nov 12th 2020 the ATSB released their final report concluding the probable causes of the serious incident were:
- The pilot of the PA-28 did not sight the ATR aircraft, which the controller had instructed them to follow, and did not advise the controller they did not have the aircraft sighted before turning on to the base leg of the circuit in front of the ATR aircraft, resulting in a near collision.
- The crew of the ATR were aware that there was traffic in the area but did not assess the position of the PA-28, in relation to their aircraft until activation of the TCAS TA.
- The controller did not seek confirmation that the pilot of PA-28 had sighted the ATR before diverting attention to an aircraft outside the circuit area. This interrupted the effective monitoring of the aircraft in the area and the developing near collision was not identified.
Other factors that increased risk
- The controller did not confirm the pilot of PA-28 correctly understood the planned method of sequencing the two aircraft.
The ATSB reported the attention of the tower controller was turned to a third aircraft departing Albury for about two minutes and 14 seconds after the last transmission to the PA-28 until the ATR crew reported they were going around. The controller thus did not notice the developing conflict.
The ATSB reported the pilot of the PA-28 (subsequently also called XDI) was an international student who had obtained his PPL just the day before the occurrence and had successfully completed the Aviation English language test about 2 months before the test. On the day of the occurrence he was performing a navigation exercise for his CPL training syllabus. The PA-28 pilot had correctly understood the instructions by tower and in particular that he was number 2 behind the ATR.
He was aware of only one other aircraft in the circuit and thus was not aware that there were three aircraft operating in the vicinty of Albury, the pilot also did not relate the callsign of the conflicting aircraft to be a commercial flight. The ATSB summarized further testimony by the PA-28 pilot:
After joining downwind, the pilot assumed the crew of the aircraft to be followed (Velocity 1174) had sighted XDI. Before turning on to the base leg of the circuit, the pilot recalled carrying out normal visual checks to ensure the base and final legs were clear. The check did not involve looking along the long final flightpath, as the pilot assumed that Velocity 1174, which had been cleared to land before XDI joined downwind, was either on short final or had landed.
The ATR had been operating in cloud descending out of cloud at about 4000 feet AGL. The first officer, pilot monitoring, was aware of another aircraft in the circuit, however, did not assess their position in relation to their path as the aircraft had been instructed to follow them.
The ATSB summarized their further testimony:
The crew advised completing their required pre-landing checklists when the captain, who was the pilot flying, detected the TCAS TA. They immediately began scanning to visually acquire the aircraft. They advised that, as they sometimes received traffic advisories during approach from aircraft operating on the ground or at low level near an airport, they initially started looking on the runway surface. The TCAS display gave an indication that the aircraft was operating in the forward right quadrant from the aircraft. The first officer quickly identified the PA-28 on the base leg of the circuit and assessed that the aircraft, while very close, would pass behind them. The captain immediately initiated a missed approach.
The TCAS system was designed such that when the aircraft was on descent and passed below 900 ft AGL, the system would not generate a resolution advisory (RA) or an aural alert. The crew advised that they have regular training on responding to a TCAS RA, but have not discussed how to manage a TCAS TA during an approach when the aircraft is below 900 ft and the RA and aural warning functions were inhibited.
The ATSB analysed:
The pilot of XDI understood the requirement to track as number two to the ATR, but was unaware Velocity 1174 was a transport category aircraft conducting a straight-in approach to the airport.
The assigned traffic sequence was intended to ensure separation was maintained, and hence it is likely the controller assessed that XDI was not significant traffic for the ATR, and did not pass traffic information to its crew. Nevertheless, the crew of the ATR were aware that an aircraft was operating in the area, but did not visually assess the position of XDI in relation to their approach path until the activation of the TCAS TA.
As the ATR was cleared to land prior to the PA-28 entering the circuit area, the pilot of XDI assumed the ATR was either on short final or had landed before XDI turned on to the base leg of the circuit. Consequently, they did not check for aircraft on long final before turning base. However, when the pilot of XDI did not report sighting the ATR as expected, the controller was required to obtain corroborative evidence from the pilot on the position of the ATR. This was a missed opportunity by both the pilot and the controller to ensure separation was maintained.
While there was no requirement for the controller to provide separation between the two aircraft, the potential conflict between them had been identified by the controller and a plan established to sequence their approach. The controller passed responsibility for separation to the pilot of XDI with the instruction to sight and follow the ATR. However, they did not require the pilot of XDI to readback the instruction, removing the opportunity for the controller to confirm the pilot correctly understood the sequencing plan.
Additionally, once the instruction was given to the pilot of XDI, the controller focussed their attention on the third aircraft. This resulted in limited visual scanning of the ATR and PA-28, which in turn prevented visual identification of their developing proximity. In combination, these factors led to the near collision not being identified by the controller or the pilots until the crew of the ATR received the TCAS TA and reported commencing the missed approach.
Flight trajectories (Graphics: ATSB):
