Reference number
Date reported
Published date
Concern summary

Safety concern regarding Sydney TCU staffing and operational concerns

Reporter's deidentified concern

A number of reporters have approached the ATSB with safety concerns regarding the staffing levels and resulting reduced capability of the Sydney Terminal Control Unit (TCU). The reporters state that a lack of appropriately qualified controllers within the Sydney TCU has resulted in a reduced level of safety for the day-to-day operations of this unit, and the airspace that it manages.

Staff shortages resulting in TIBA

Most recently, the terminal airspace around Sydney International Airport was forced to downgrade to Traffic Information Broadcast by Aircraft (TIBA) procedures between 2300-0600 local on 25 July, 2022. One reporter stated that the removal of critical air traffic control services such as traffic and terrain separation, as well as collision avoidance and alerts, presents an unacceptable increased level of risk at Australia’s busiest international airport. During this period, one operator was forced to cancel 14 flights and another operator required one inbound international flight to hold for 30 minutes until the TIBA period ended. The reporter states that this was presumably due to these operators not willing to accept the increased level of risk to flights operating within this environment at Sydney.

Removal of Traffic Manager

One reporter stated that as a result of recent redundancies and subsequent lack of appropriately experienced and qualified controllers, Airservices Australia (ASA) has removed the role of Traffic Manager during night shifts. The Traffic Manager role during the day shift is also subject to a daily risk management process, meaning that Traffic Managers are not always available during the day either. One reporter noted a period of 40 hours where there was no Traffic Manager on duty.

It was reported that the Traffic Manager role provides an integral level of strategic oversight and support to the line controllers who manage this airspace during a shift, and the reporter was concerned that the removal of this role unnecessarily increases controller workload and adds the associated risk of a reduced situational awareness of the line controllers.

A reporter has stated that the delegation of oversight of the Sydney TCU to the Melbourne System Supervisor in lieu of a Traffic Manager being present during the night shift does not provide adequate support or supervisory functions, due to the remote location of the Melbourne System Supervisor from the Sydney TCU control room. They have further stated that Systems Supervisor is a fulltime role, and that this workload prevents effective support being given to the Sydney TCU.

Another reporter has stated that during the past 12 months, the Traffic Manager has been integral to the safe resolution of several abnormal and/or emergency situations. The removal of the Traffic Manager raises concerns that the additional level of safety is now absent.

Additionally, as one of the duties of the afternoon Traffic Manager is to ensure that the night shift controllers consoles are correctly configured prior to signing off, there is a risk that this procedural step is missed if a Traffic Manager is not present during the day shift for hand over. One reporter was aware of an instance that has been reported to ASA where a night shift line controller’s Short Term Conflict Alarm (STCA) was not enabled in the absence of a Traffic Manager being present during the night shift hand over, and as a result this safety critical function was not available to controllers conducting Reciprocal Runway Operations at Sydney during that night shift.

Another reporter has advised that the incorporation of non-controller qualified Operational Support personnel, in lieu of a Traffic Manager during the day shift, has often resulted in these personnel carrying out duties that they are not qualified to undertake. The reporter has stated that they were aware of examples of Operational Support personnel approving live firing exercises within Sydney airspace, approving the removal of navigation aids for maintenance, issuing NOTAM’s and conducting handovers to oncoming air traffic control staff – all of which is beyond the duties and qualifications of Operational Support personnel, and likely carried out with the intention of trying to reduce line controller workload in lieu of a qualified Traffic Manager being present.


One of the reporters further stated that to replace the functions of the Traffic Manager on affected shifts, line controllers have been provided with a Quick Reference Guide. This guide contains a number of procedures that are either incomplete or do not align with ASA policies – often resulting in controllers ‘making it up themselves’. An example the reporter has shared is this document being an amalgamation of several source documents and often is not coherently presented, with the result that a user following the steps contained in it, is often referred to additional steps or appendices that have not been included within the guide itself – requiring controllers to leave their station and retrieve the relevant source document while potentially handling an emergency situation or during a period of high workload. The reporter has further stated that whilst the guide contains information around how the STCA is to be configured, there is no requirement contained within the document for line controllers to carry out this task in the absence of a Traffic Manager at handover prior to the night shift, as detailed earlier.

ATSB Comment: The ATSB notes ATC incident report [number] relating to the inability to change a runway during a period where it was forecast that it was likely required. The report referencing that current ASA procedures do not provide direct guidance for operations with both the Traffic and Flow managers roles being vacant simultaneously during a shift.

Temporary Local Instructions

A further reporter has raised concerns regarding the process of issuing Temporary Local Instructions (TLI) within the Sydney TCU. They have stated that in the past TLI’s would routinely be issued to controllers well in advance of their becoming effective, allowing controllers to become familiar with any operational changes and raise any concerns or queries via the Cirris reporting system within a reasonable timeframe. They have stated that in a number of recent cases this process has not been followed, resulting in significant operational changes being implemented with immediate effect, mid-shift and requiring controllers to implement and adopt these changes ad-hoc. A recent example given relates to the policy of the increase in required separation to be applied to inbound aircraft to Sydney, with controllers expected to adopt this change with no prior notice and with immediate effect during a shift.

In summary, the reporters are collectively concerned that staff shortages and a lack of appropriately qualified and experienced controllers within ASA is resulting in a reduced oversight and lack of support to line controllers at Sydney TCU. Combined with the incomplete support mechanisms and documentation to manage the removal of Traffic Managers, and an inadequate change process around TLI’s, the reporters believe that the safety critical functions that ATC provide are now being compromised.

Named party's response

Staff shortages resulting in TIBA

The report implies that the Sydney Terminal Control Unit (TCU) does not have sufficient operational Air Traffic Controllers (ATC) to provide the necessary service. This implication is not correct and a recent surveillance event by the Civil Aviation Safety Authority (CASA) did not raise any findings in relation to ATC staffing at the Sydney TCU. However, as with all organisations, ASA is experiencing higher levels of staff unavailability due to COVID-19, influenza and other related sickness. On 26 July, we experienced late notice unavailability of staff to fulfil a shift in the Sydney TCU. All reasonable steps were taken to see if the shift could be filled and when this was not possible, contingency measures were put in place which included the use of Traffic Information Broadcast by Aircraft (TIBA). The TIBA was communicated to all operators, including those with international flights where the information was provided in advance of their departures. However, ASA could not comment on the decision-making processes of operators in these circumstances but is confident that our contingency procedures are safe and fit for purpose.

Removal of Traffic Manager

The report states that the removal of the Traffic Manager role overnight is again linked to having insufficient numbers of operational staff. Again, this is not correct and the change had been under consideration since 2018. In undertaking this change, a comprehensive risk and change management process was undertaken and all appropriate processes have been followed to support the implementation of this change to the Sydney Traffic Managers hours of coverage. The specific occurrence related to the enablement of the Short Term Conflict Alert (STCA), like all reported occurrences, was reviewed and managed through the ASA Safety Management System (SMS), noting that information errors are made similar to those noted in the report regardless of whether there is a Traffic Manager present, and there are systemic controls to mitigate risks that relate to these types of human errors. ASA notes the comment around availability of the Traffic Manager during the day which has in part been a direct result of the short notice and unexpected resignation of a Traffic Manager. ASA has been seeking to endorse additional Traffic Managers but has faced challenges with protracted training and unsuccessful endorsement checks. In all cases where there is a period of coverage without an endorsed Sydney Traffic Manager present, all documented contingency processes are followed. In all cases where a NOTAM is required to be issued, these are approved and actioned through the Flight Information Region (FIR) Operational Command Authority (OCA) and the related applicable authorities.

ATSB comment: The ATSB notes that the reporters’ concern regarding the incorrect configuration of the STCA, as described in the REPCON, relates to the lack of a systemic control to ensure that this task is completed in the absence of a Traffic Manager during handover, and not the individual actions of the line controller involved.

ATSB comment: The ATSB notes that the ASA response does not address the reporters’ concerns regarding a Traffic Manager not being present in the Sydney TCU for a period of 40 hours, encompassing both day and night shifts.


The purpose of the Quick Reference Guide (QRG) was to provide a resource that would support ATC in functions that they may not have managed or experienced on a regular basis, and is not intended to replace the primary parent document and their procedures and content. As for all ATC nationally performing their role during low traffic periods without direct supervision, it is the expectation that controllers utilise all available reference documents to support the exercising of their licensed role.

In regard to ATS-0189554, ASA acknowledges the potential situation and on the day a Flow Controller was bought in early for their shift to enable a runway change should it have been required. As a result of the reported occurrence we are investigating changes to contingency procedures to mitigate this potential situation.

Temporary Local Instructions

ASA has processes for the production and publication of controlled documents including Temporary Local Instructions (TLI) and endeavours to publish a TLI in advance of their effective date. This is not always possible and it can be necessary to issue a TLI quickly in the interests of safety. To ensure ATC are aware of changes a new information register is kept.

Regulator's response

CASA is aware of the issues identified within the REPCON and is managing according to established surveillance manual procedures.

Principle to this management is that CASA conducted a surveillance activity of Sydney TCU in June/July 2022. The event resulted in the four Safety Findings and three Safety Observations. Of these, three Safety Findings and one Safety Observation related to the concerns raised by the REPCON as indicated below:

Staff shortages resulting in TIBA.

  • CASA issued a Safety Observation due to concerns over ASA having insufficient staff at Sydney TCU. The observation was based on evidence that the Airservices calculated number of staff required was insufficient to continue to provide the service. At the time of surveillance, Sydney TCU had not experienced an interruption to service.
  • A Safety Finding was issued identifying a lack of supervisory staff. This safety finding was issued against Reg 172.115 of the CASR. Evidence demonstrated that prior to removal of the overnight traffic manager, several instances occurred where traffic manager was unable to be staffed.
  • A Safety Finding was issued regarding inadequate training management on recently trained Traffic Managers. Specifically, this related to training not following a prescribed course that would ensure Traffic Managers are suitably equipped to fulfill the requirements of the role.

Removal of Traffic Manager, and Associated Procedures and Documentation.

The surveillance event was immediately prior to the planned removal of Traffic Manager. CASA issued a Safety Finding regarding ASA not following their Safety Management System in assessing this change. Specifically, the Safety Finding highlighted the fact the change was made without reference to the regulator, and thus the regulator was unable to influence implementation.   CASA continues to manage the matters raised in the REPCON, Safety Findings and Observations as outlined within the CASA Surveillance Manual. Should the matters not be resolved CASA may elevate the issues to enforcement action as outlined within the CASA Enforcement Manual.