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.

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.

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.

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.