Aviation safety issues and actions

Military ATS risk

Issue number: AR-2012-034-SI-01
Who it affects: All civilian aircraft operations into military controlled airspace
Issue owner: Department of Defence
Operation affected: Aviation: Airspace management
Background: Investigation Report AR-2012-034
Date: 18 October 2013

Safety issue description

There was a disproportionate rate of loss of separation incidents which leads to a higher risk of collision in military terminal area airspace in general and all airspace around Darwin and Williamtown in particular. Furthermore, loss of separation incidents in military airspace more commonly involved contributing air traffic controller actions relative to equivalent civil airspace occurrences.

Response to safety issue by: Department of Defence

The Department of Defence takes all losses of separation and losses of separation assurance seriously and investigates all incidents to identify causes and areas that can be improved in order to mitigate against further occurrences. To reduce the potential for separation occurrences, Defence are reviewing the implementation of the traffic management plans at Darwin, Townsville, and Williamtown to improve the effect of strategic separation techniques. These reviews will also be used to highlight any current airspace constructs that inhibit the controller’s ability to provide optimum separation assurance. Defence has also recently published an internal capability improvement plan that focuses on increasing experience levels at Defence air traffic locations. To improve our ability to respond to potential losses of separation, Defence has enhanced the School of Air Traffic Control simulator packages to provide greater exposure to compromised separation occurrences, with the trainee being assessed on their ability to apply compromised separation recovery. Defence has also added both theoretical and practical assessment to local training packages regarding scanning for possible losses of separation and applying compromised separation recovery techniques when required.


ATSB comment in response

The ATSB acknowledges the intended action by the Department of Defence, but considers that a broader review of Defence ATC processes and risk controls should be undertaken, including analysis of ATS related occurrence data, training, staffing and ATS infrastructure to ensure the reasons for the disproportionate risk of loss of separation incidents, and the relative higher level of controller actions contributing to these occurrences, are well understood and any additional appropriate action can be taken to minimise future risk. As such, the ATSB is issuing the following recommendation.


Action organisation: Department of Defence
Action number: AR-2012-034-SR-014
Date: 18 October 2013
Action status: Released

The Australian Transport Safety Bureau recommends that the Department of Defence undertake a review of all processes and risk controls in place to reduce both the disproportionate risk of loss of separation incidents in military terminal area airspace in general and all airspace around Darwin and Williamtown in particular, and the relatively more common contributing air traffic controller actions.


Date received: 20 January 2014
Response from: Department of Defence
Action status: Monitor
Response text:

Thankyou for your letter of 11 October 2013 regarding the advance release of the report titled Loss of separation between aircraft in Australian airspace. Whilst I appreciate the opportunity to provide feedback during the directly involved party process and note that some changes were made to address Defence concerns in previous correspondence, I feel that Defence feedback was not clearly understood or considered.

In accordance with Section 25A (2) of the Transport Safety Investigation Act 2003, I hereby advise the ATSB that Defence does not agree with the Safety Recommendation AR- 2012-034-SR-014. The report insufficiently acknowledges the unique context of military operations and the role of the Defence Aviation Safety system. Despite the vast majority of incidents occurring in civil airspace, the report remains negatively biased against military airspace and is based on a subjective comparison of military and civil Air Navigation Service Providers. Therefore, Defence disagrees with the report's conclusions and recommendations.

Whilst Defence does not support the report, as a proactive safety organisation we will continue to implement changes to further enhance safety and commit to reducing our loss of separation rate. Defence will continue to improve air traffic control workforce capability, increased practical simulator training and update air traffic management plans. Additionally, a joint Civil Aviation Safety Authority-Defence aeronautical study will be conducted of RAAF Base William town in 2014, with the scope for future joint studies at other locations.

ATSB response:

The ATSB remains concerned that the Department of Defence does not accept that, although military controlled airspace represents only a small proportion of total Australian controlled airspace, the risk associated with loss of separation is disproportionally high relative to the number of aircraft movements compared to civil controlled airspace.

The ATSB welcomes the promised joint-safety study at Williamtown in 2014 and other defence airfields in the future. Loss of separation involving civilian aircraft in military controlled airspace will continued to be closely monitored by the ATSB until this time. The Safety Recommendation will remain open until the ATSB has assessed the outcomes of the review at Williamtown.

Date received: 06 October 2016
Response from: Department of Defence
Action status: Monitor
Response text:

Defence has taken a number of steps to respond to recommendation and have been providing periodic updates to the Aviation Policy Group. A response documenting all safety actions will be provided to the ATSB in December 2016.

Date received: 06 September 2017
Response from: Department of Defence
Action status: Monitor
Response text:

Defence continues to implement the recommendations associated with the October 2015 Joint CASA and RAAF Aeronautical Study of Williamtown Airspace. While many of the recommendations have already been implemented, numerous recommendations primarily concern civil aviation; such as those associated with civil instrument flight procedures, air routes and civil-military traffic management planning. As many of the recommendations fall outside the purview of Defence, in November 2016 the Aviation Implementation Group agreed to establish a working group to develop a strategic implementation plan for all recommendations requiring inter-agency collaboration and to provide periodic updates to the Aviation Implementation Group. The Aviation Implementation Group has also recognised that an absence of national policy guidance on which agency is responsible for design and maintenance of civil instrument flight procedures is another area that requires resolution to inform the way forward.

The strategic implementation plan will inform further Defence response to AR-2012-034-SI-01, as it pertains to initiatives that will further reduce the risk of loss of separation incidents. Defence looks forward to providing another update to the ATSB following the next Aviation Implementation Group which is scheduled for November 2017.

Current issue status: Safety action pending
Last update 29 November 2016