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Mode Aviation
Reference No. AR201500056
Date reported 03 July 2015
Concern title Management not utilising all available resources during unplanned air traffic control staff shortages
Concern summary

The concern related to the management processes used during an unplanned air traffic control staff shortage which led to a situation where the controllers were placed under high workload with no breaks.

Industry / Operation affected Aviation: Airspace management
Concern subject type Aviation: Air Traffic Control

Reporter's concern

The reporter expressed a safety concern relating to the staff shortages at the ‘Byron’ ATC group at Brisbane Centre Enroute section. The section in question contains the Byron / Inverell sectors which process traffic inbound and outbound for Brisbane and the Gold Coast and military aircraft for Amberley.

The reporter advised that recently the section, which normally requires between 3-4 controllers, was operated for an extended period with only two controllers. Only one of these controllers was qualified to operate both the Gold Coast and Inverell, the other was qualified on the Inverell area only. With only two controllers there was no-one to fill the planning position, provide required breaks, provide a spotting service as the controllers began to fatigue or replace a controller in the event of an incident.

During this extended time, the controllers had a high workload which under normal circumstances would have required them to have a break or have a qualified controller assisting them to ensure safety. To assist, a controller who is not qualified was brought in to operate the planning position which is contrary to Byron Local Instructions.

Operator's response (Operator 1)

Airservices would like to provide the following background of the staffing issue, its management and actions taken to address the lessons learned.


Byron Group is an Enroute Group which provides surveillance arrivals and departure services to the Gold Coast and an arrivals and departures service from the south into Brisbane. The Group is comprised of two sectors named Inverell (INL) and Gold Coast (GOL). There are three endorsements which Air Traffic Controllers (ATC) can hold within the Group:

  1. Inverell - INL
  2. Gold Coast - GOL; and
  3. Byron Planner - BYP

The following daily hours of operation (specified in local time) are the basis for determining Byron roster requirements. These hours apply to each day of the week.

  • INL console: 0000 - 2400 (24-hour operations)
  • GOL console: 0545 – 2200
  • BYP console: Nil (used as and when required).

Actual console utilisation and hours of operation may vary from the above dependent upon operational requirements.

The following is a typical roster for Monday to Friday.

 A typical roster for Monday to Friday


The Group is comprised of 18 Air Traffic Controllers who hold a mixture of the required endorsements. Historically, the Byron shifts were 3 controllers in the morning and 3 in the afternoon, supplemented by an Additional Duty (AD) shift during severe weather events.

With the suspension of Converging Runway Operations (CROPS) in Brisbane several years ago, the 1130-1930 shift was introduced to address the resulting severe holding in the afternoons. Since METRON was introduced into Brisbane, the extensive holding does not routinely occur and the 4th afternoon shift is typically used by controllers to provide an hour on, hour off work pattern on fine weather days.

Sequence of event leading to and on [date]

During the previous week, the Byron group had 7 controllers absent, of which 3 were planned and 4 unplanned due to a combination of annual leave, sick leave and special leave.

The level of unplanned absenteeism placed a significant strain on the roster. The Byron group ATC Line Manager (ALM) emailed the group's controllers on [five days before the event], outlining the rostering shortfalls in the coming week and requesting volunteers to cover the additional shifts (including the vacant 1130-1930, [date] shift). No replies were received and the shift remained unfilled on [the day before].

On the afternoon of [the day before], the Byron group ALM requested the controller who was due to start at 1300 on [date] to commence duty at 1200. The controller declined to due to a prior engagement, which meant that there were two suitably qualified and endorsed Air Traffic Controllers rostered for the period 1130 - 1300.

An informal assessment of the predicted workload and weather was made by the morning shift manager and the Byron group ATC Line Manager in conjunction with the rostered Byron ATC staff in early morning on [date]. It indicated no foreseeable spikes in workload and the weather was deemed to have no impact on normal operations.

A seating plan was made to ensure that no controller was required to sit at the console for a period greater than 2 hours consistent with the ATC Enterprise Agreement. The recency records show that both controllers worked a maximum of 2 hours in a single block on the day. Prior to this block, both controllers had worked for 30 minutes after which they had taken a 30 minute break.

At approximately 1200 a handover/takeover was conducted between the morning and afternoon Shift Manager when the staffing considerations on Byron were highlighted. At this stage, no traffic management measures such as metering had been implemented as there was no indication of the subsequent increase in workload.

By approximately 1220 traffic had increased significantly with a high number of departures from Brisbane, the Gold Coast and Amberley, which resulted in a large number of aircraft simultaneously climbing, descending and crossing tracks. A suitably qualified controller from an adjacent sector was utilised to perform spotting duties to assist the INL Controller with their scan.

Traffic Metering was implemented immediately by the Shift Manager with 5 minute departure spacing required out of Brisbane and the Gold Coast for all traffic to the south.

Management of staffing issue

Airservices confirms that attempts had been made to replace controllers impacted by planned and unplanned leave leading up to [date]. However no replacement could be found. In addition, staff had been asked to extend their nominal shift but this effort was also unsuccessful. When no suitable replacement was identified, an assessment of the operating environment was conducted considering workload, weather and planned military activity.

While staffing on [date] was at the minimum allowable level, sufficient suitably qualified staff were available at all times. No controller was required to work for a period exceeding 2 hours, which is compliant with the hours of work clause in the ATC Enterprise Agreement.

The use of a licenced air traffic controller from an adjacent group to perform spotting duties to assist the INL Controller with their scan is an appropriate mitigation measure in the absence of other Byron staff being available.

Lessons learned and actions

In reviewing the reported concern, Airservices has identified that while effort to replace controllers was made, no formal risk assessment was undertaken when determining whether to replace the shift.

Surrounding sectors had not been advised of the staffing on the Byron group for the period 1130 - 1300 and as such no proactive traffic management plan had been developed or implemented prior to 1220 which may have assisted in the tactical workload management of the Byron controllers when workload and complexity subsequently increased.

As a result, Airservices has identified the need to be more thorough in assessing the impact of staffing at the minimum level. A risk assessment template has been created to improve the documentation of considerations given and actions implemented by the holder of Operational Command Authority in these situations. It is also to ensure that surrounding ATC Units are notified and, where deemed necessary and appropriate, a coordinated Traffic Management Plan is implemented.

Regulator's response (Regulator 1)

CASA has reviewed the REPCON and notes the comments from Airservices.

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Last update 31 August 2015