CASA partially accepts the recommendation in as much as CASA has reviewed the report and will take action as detailed below.

CASA is limited in its ability to influence military ATS in relation to the safety of civil aircraft using military airspace as regulation 172.005 of the Civil Aviation Safety Regulations 1998 provides Part 172 does not apply to a person providing an ATS for the Defence Force, or any ATS provided by the Defence Force.

CASA undertakes many activities in its regulation of civil aviation in Australia. CASA activities include coordinated activity with Defence, the lead regulatory role in the OneSky Australia project (a joint civil military project), observing Defence audits, providing advice to Defence on specific operational matters where requested and the conduct of aeronautical studies of Australian airspace including Darwin, Townsville and Williamtown.

Future actions that will be undertaken include the conduct of a joint aeronautical study of the airspace around RAAF Base Williamtown and working with Defence and Airservices Australia to address issues relating to traffic growth, airspace complexity, airspace efficiency and airspace design. The provision of ATS in this airspace, including Restricted Areas, will be within scope of the study. In carrying out these actions, CASA seeks to be assured that the safety of civil aircraft operations while under military control is adequate. CASA will continue to engage with the Department of Defence, Airservices Australia and the Department of Infrastructure and Regional Development to ensure that safe services are provided.

The ATSB welcomes CASA’s intention to participate in a joint safety study of Williamtown, and notes that part of the aim for this study is for CASA ‘to be assured that the safety of civil aircraft operations while under military control is adequate’.

The Safety Recommendation will be set to ‘monitor’. The ATSB will seek CASA’s advice, subsequent to the completion of the Williamtown study, as to whether CASA considers its current level of oversight of civilian operations while under military control is adequate.

The Civil Aviation Safety Authority (CASA) notes the Safety Recommendation will be set to 'monitor' in the ATSB database tracking system and ATSB will seek CASA's advice, subsequent to the completion of the Williamtown study, as to whether CASA considers its current level of oversight of civilian operations while under military control is adequate. When that is completed, CASA will provide a brief to ATSB on the outcomes of the Williamtown aeronautical study.

CASA has reviewed the outstanding agreed actions list and believes we are in a position to update and close Safety Recommendation AR-2012-034-SR-015.

With regard to this Safety Recommendation, the ATSB recommended CASA review the results of this report and determine whether its current level of involvement with military air traffic services (ATS) is sufficient to assure itself that the safety of civil aircraft operations while under military ATS control is adequate.

As explained at the ATSB/CASA liaison meeting on 17 December 2014, the ATSB was previously advised that the Aeronautical Study of the airspace around Williamtown was intended to provide the assurance regarding the operation of the ATS. This was incorrect and CASA apologises if this caused any misunderstanding. It was also explained that CASA has an arrangement with Defence for the observation of Defence audits at Defence ATS units, with reciprocal opportunities for Defence observers at our audits of Airservices' units. This had originally been advised to ATSB during the DIP consultation and was acknowledged in the final report.

It was further outlined that CASA had observed a recent operational evaluation of Williamtown, the main features of which were:

• A CASA Airspace and Aerodrome Air Traffic Control (ATC) Inspector attended a five-day RAAF Operational Evaluation (RAAF Audit) at RAAF Base Williamtown;
• The RAAF Operational Evaluation process was observed and found to be adequate;
• The ATC between multiple civil and military aircraft and between civil aircraft was observed: all aircraft were, without exception, processed and separated in accordance with the Manual of Air Traffic Services (a joint civil/military document);
• The RAAF were very open and inclusive with CASA participation in the Operational Evaluation;
• All CASA's suggestions and recommendations were accepted. These related to: audit process to be changed to align more with that described in the CASA Surveillance Manual, less formal examinations and more interview style questioning of auditees, a more systemic approach to surveillance and audio sampling of Radio Telephony for compliance with standard phraseology; and
• CASA also discussed Williamtown A TC with Airservices at the Brisbane ATC Centre and discussed Williamtown operations with Airservices controllers with no major issues to report.

In concluding this work CASA assured itself that the safety of civil aircraft operations while under military control was adequate.

CASA believes that the above recommendation has now been addressed and can be closed.

The ATSB has been monitoring the outcome of this safety recommendation based on CASA's initial advice (8 January 2014):

".... actions that will be undertaken include the conduct of a joint aeronautical study of the airspace around RAAF Base Williamtown and working with Defence and Airservices Australia to address issues relating to traffic growth, airspace complexity, airspace efficiency and airspace design. The provision of A TS in this airspace, including Restricted Areas, will be within scope of the study. In carrying out these actions, CASA seeks to be assured that the safety of civil aircraft operations while under military control is adequate."

However, CASA advised the ATSB on the 27 January 2015 to the contrary. The ATSB notes that CASA' s proposed action to 'conduct of a joint aeronautical study of the airspace around RAAF Base Williamtown and working with Defence and Airservices Australia to address issues relating to traffic growth, airspace complexity, airspace efficiency and airspace design' is now considered not appropriate by CASA to address this safety recommendation. Due to this, the remaining safety action taken by CASA, involving a routine observation of a Defence audit of Williamtown ATS alone, does not appear to be a systematic evaluation of all military ATS involvement with civil aircraft. The ATSB believes that CASA should do further work to assure itselfthat the safety of civil aircraft operations while under Military ATS control is adequate.

The ATSB will leave the safety recommendation AR-2012-034-SR-015 on monitor pending any further safety action advice from CASA.

CASA reviewed the report and undertook to assure itself within the limits of its powers of the safety of civil aircraft operations while under Military A TS control. This was the subject of CASA's letter of 27 January 2015.

In the response from Martin Dolan dated 13 March 2015 it was stated that the, "safety action taken by CASA, involving a routine observation of a Defence audit of Williamtown ATS alone, does not appear to be a systematic evaluation of all military ATS involvement with civil aircraft. The ATSB believes that CASA should do further work to assure itself that the safety of civil aircraft operations while under Military ATS control is adequate."

CASA is only permitted to observe Defence audits of Defence ATC units with the agreement of the Department of Defence. CASA has no powers to carry out, "a systematic evaluation of all military ATS involvement with civil aircraft". CASA has taken the only action it is empowered to take under the legislation.

The ATSB report stated that the rate of Loss of Separation (LOS) and Loss of Separation Assurance (LOSA) was higher for RAAF Base Williamtown than any other ATC unit in the country. However, ATSB does not indicate whether this rate is acceptable. There will always be one ATC unit with the highest rate and this fact must be considered in relation to whether that rate is acceptably safe. As the ATSB has not stated that the rate is unacceptable, the conclusion is drawn that ATSB considers the rate acceptable.

CASA oversights the operation of civil public transport aircraft operators using Williamtown. Aircraft operators holding an Aircraft Operators Certificate (AOC) must either have the aerodromes to which they operate approved and listed on their AOC or have in place a system for safety-assessing ports before operating to them. This process applies whether the aerodrome is civil, military, in Australia or overseas.

CASA has assured itself to the best of its ability of the safety of the air traffic services provided at Williamtown.

CASA considers that, as the current policy and legislation stands, the matter of the regulation of Defence ATS is one for the Department of Defence and, ultimately, the government.

CASA believes that the above recommendation has now been addressed and can be closed. Can you please review this information and confirm that the ATSB will close the recommendation tracking and amend the ATSB web site and database accordingly.

That letter [from CASA on 2 July 2015] stated:

'The ATSB report stated that the rate of Loss of Separation (LOS) and Loss of Separation Assurance (LOSA) was higher for RAAF Base Williamtown than any other ATC unit in the country. However, A TSB does not indicate whether this rate is acceptable. There will always be one A TC unit with the highest rate and this fact must be considered in relation to whether that rate is acceptably safe. As the A TSB has not stated that the r.ate is unacceptable, the conclusion is drawn that ATSB considers the rate acceptable.'

The ATSB research investigation report actually concluded that the rate of LOS across all military aerodromes was higher than civil aerodromes, and that both Williamtown and Darwin were particularly notable examples of this. This conclusion was based not only on the rate of LOS at the Tower and Terminal Area environments, but also based on collision risk, event risk (taking into account the size of aircraft), the involvement of contributing errors by air traffic controllers, and the reliance on controllers to employ tactical separation in lieu of strategic separation. Therefore, the ATSB believes it is inappropriate for CASA to consider Williamtown simply as the aerodrome that happened to have the highest LOS rate. The ATSB has not commented on whether the risk concerning LOS in military airspace is acceptable, but has noted that military air traffic services do not appear to assure the same level of safety to civilian aircraft as do civil air traffic services.

The 2 March 2015 letter also stated:

'CASA is only permitted to observe Defence audits of Defence ATC units with the agreement of the Department of Defence. CASA has no powers to carry out, "a systematic evaluation of all military ATS involvement with civil aircraft". CASA has taken the only action it is empowered to take under the legislation.
......
CASA considers that, as the current policy and legislation stands, the matter of the regulation of Defence ATS is one for the Department of Defence and, ultimately, the government.'

The ATSB acknowledges that, as current policy and regulations stand, CASA has limited opportunity to assure itself of the safety of civil aircraft in military airspace. However, given that the safety of the travelling public is a primary function of CASA, and that the ATSB has identified through a comprehensive and sound analysis of the data that military air traffic services do not appear to assure the same level of safety to civilian aircraft as do civil air traffic services, it is hard to reconcile CASA's apparent reluctance to engage with the issue. If CASA cannot assure itself of the safety of the travelling public under current legislation, it would seem that it is within CASA's powers to consider altering current regulations to enable it to have that assurance.

In the light of this, the ATSB Commission is not satisfied that CASA has taken sufficient steps to assure itself that the safety of civil aircraft operations while under military air traffic control is adequate. As a result, the ATSB will not be closing this recommendation and seeks CASA's further consideration and advice of what it may do to address this issue.

As you are aware, this matter is being dealt with through the Aviation Policy Group (APG). Discussions have taken place at the highest levels (APG) between CASA, Defence and the Department of Infrastructure and Regional Development. The Department is drafting a paper which will include options for different levels of oversight. It is my understanding discussions on this matter will continue in 2016.

I would like to point out that while Safety Recommendation AR-2012-034-SR-015 has been issued to CASA, the subject is not solely CASA's responsibility. There is a significant military aspect and CASA will not be able to progress safety action without Department of Defence involvement and Airservices Australia. However it is my intention to continue further dialogue with the Department, Department of Defence and Airs~rvices to achieve a satisfactory outcome.

The ATSB believes the discussions held by the Aviation Policy Group are very encouraging and show that all parties involved are working together to find a long-term solution to this safety issue. The ATSB will continue to monitor this recommendation while this work continues.

Since this safety recommendation was issued, CASA and Defence have been collaborating and through the Aviation Policy Group (APG) have jointly developed a policy covering the safety oversight of civil operations into joint user and military airports.

The policy comprises a subordinate agreement to the primary CASA/Defence agreement on safety and airworthiness. The APG, at the 8 September 2016 meeting, endorsed the subordinate agreement and it was subsequently signed by the CASA Director of Aviation Safety and Chief of Air Force. The subordinate agreement is titled 'Topic Area: Transparency of Safety Oversight of Delivery of Defence ATS to Civil Aviation Operations', and CASA and Defence have now commenced implementation of the arrangements.

[The ATSB notes the scope of the agreement is:

Defence continues to provide its own safety oversight of the provision of ATS to civil aviation operations. CASA will observe systems and operational assessments conducted by Defence of Defence ATS operations, and engage in Defence regulatory discussions and forums, to the degree necessary to satisfy CASA that the level of Defence safety oversight and delivery of ATS to civil aircraft is comparable to that provided under CASR Part 172.

Further, the ATSB notes activities in the agreement are:

1. Identification of specific CASA and Defence personnel/appointments to form the focal points.
2. Standing participation of CASA focal points at the periodic Defence ATM Airworthiness Boards (AWB), with access to relevant AWB documentation. CASA will provide the AWB with a general report including matters of safety interest to CASA and all CASA observations applicable to civil aircraft operations at joint user and military airports and within military administered airspace.
3. Regular participation by CASA focal points in Defence ATM Operational Evaluations (OPEVAL) and other regulatory or surveillance activities which may include coordination with applicable Defence aviation stakeholders;
a) CASA will not formally assess Defence personnel, ATC procedures or systems and infrastructure at these events;
b) CASA will raise with Defence any matters of safety interest identified by CASA in the context of CASR Part 172 as applicable to the operation of civil aircraft within Defence aviation environments;
c) CASA will track participation in Defence OPEVAL and other regulatory activities through CASA's Sky Sentinel software application, recording any safety concerns identified to Defence as CASA 'Observations' within Sky Sentinel; and
d) Defence will address any CASA recommendations and Observations and respond accordingly, consulting where applicable with aviation users in order to pursue an optimal outcome.
4. In order to enhance Defence understanding of the practical application of CASR Part 172 in the civil environment, subject to CASA coordination with, and approval by, Airservices on a case-by case basis, regular observation by Defence focal points of CASA surveillance activities at selected civil ATC locations.
5. Mutual participation in CASA and Defence regulatory discussions and forums to facilitate the transparency of safety oversight of civil operations at joint user and military airports and within military administered airspace.]

Additional actions in support of the transparency of oversight agreed by the APG include that:
• the primary CASA/Defence Safety and Airworthiness agreement and the subordinate agreement be published on each agency website
• for the next two years CASA and Defence provide regular updates to the APG on the implementation of the arrangements and activities conducted
• re-evaluation of the arrangements take place after two years, involving Defence, CASA, Airservices and the Department of Infrastructure and Regional Development, and the outcomes and proposed actions be reported to the APG.

As a result of the implementation of the subordinate agreement and the complementary additional actions agreed by the APG, CASA considers that Safety Recommendation AR-2012-034-SR-015 has been addressed.

The ATSB welcomes this landmark agreement between CASA and Defence as a positive and transparent approach to cooperation that should ensure that CASA can assure itself of the safety of civilian aircraft in military airspace. The ATSB has closed this recommendation.