Airservices Australia did not have procedural controls to separate aircraft concurrently carrying out the MARUB SIX standard instrument departure and a missed approach from runway 34R at Sydney Airport while below the minimum vector altitude at night.
The safety actions implemented by Airservices Australia should adequately address the safety issue.
In February 2020 Airservices advised that it would:
Conduct a risk assessment of MARUB SIX SID and missed approach operations on runway 34R at night to inform an options analysis to improve the effectiveness of system defences.
Subsequently, Airservices redesigned the missed approach for the Runway 34R instrument landing system (ILS) and ground-based augmentation system landing system (GLS) approaches, effective 2 December 2021.
Airservices reported:
The [runway 34R] missed approach now has a turn point that closely replicates where an aircraft on the MARUB SID [standard instrument departure] would commence turning. This provides an increased likelihood that distance will be maintained longitudinally between the aircraft. The MARUB SID has a tighter turning requirement ([minimum angle of bank] 25°) and steep climb gradient (4.8% to 1500ft, then 3.3%) which should prevent the missed approach aircraft from turning inside the departing aircraft. The MARUB SID turns to intercept the 075° track whilst the missed approach turns to a point and then tracking 060° which will permit divergence between the aircraft.
The ATSB welcomes the safety action to reduce the likelihood of converging flight paths between aircraft flying these procedures concurrently, noting also that the later, and defined, missed approach turning point also should result in:
The ATSB also notes the complexity of designing procedures to minimise conflict, especially in the case of a missed approach with other aircraft departing the same runway, as there are many factors that Airservices is required to take into account. The ATSB urges Airservices to apply its expertise and data to monitor the safety outcomes on an ongoing basis so that the lowest-risk designs can be identified and implemented in the long term.
In February 2020 Airservices advised that:
Specific compromised separation scenarios where an aircraft is operating below the MVA [minimum vector altitude] at night [were] to be included into the Sydney Tower Instructor Guide.
On 14 June 2023 Airservices advised that:
The missed approach with a preceding departure in IMC [instrument meteorological conditions] is [now] included in the Sydney Tower training program. Airservices is working to have the same scenario, night time operations, included in the compromised separation recovery simulator training for all Capital City towers.
