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Air traffic management

Communications, navigation, surveillance/air traffic management

Airspace capacity is determined by the combined capabilities of the communications, navigation, surveillance and air traffic management systems (CNS/ATM) in place. These include ground and aircraft-based systems and requirements vary according to the airspace being considered.

We have regulations and aircraft equipment mandates in place to support CNS/ATM. These mandates implement Performance-Based Navigation (PBN), Mode S Transponders and Automatic Dependent Surveillance-Broadcast (ADS-B) to provide the navigation and surveillance capabilities needed to improve air traffic management efficiency and harmonise Australian operations with global standards.

General information

From 6 February 2014, all aircraft new to the Australian register on or after this date that operate instrument flight rules (IFR) must be equipped with Technical Standard Order (TSO) C145, C146 or C196 global navigation satellite system (GNSS) unless they are equipped with a multi-sensor navigation system that includes GNSS – inertial integration acceptable to CASA. Details of the equipment changes and the applicable dates are provided in the links below.


The communications element of CNS/ATM is evolving with technology. Emerging communications technology is enabling more use to be made of Datalink communications in lieu of the legacy VHF and HF voice communication systems. However, for most operations the primary means of communications will continue to be VHF and HF voice.

This section contains information relevant to aircraft communications.


Air navigation in continental airspace is transitioning from conventional ground-based radio navigation aids to Performance-Based Navigation (PBN); in Australia the PBN implementation is based on Global Navigation Satellite Systems (GNSS). GNSS is also being used in oceanic regions to provide a PBN solution.

From 4 February 2016 all aircraft operating in Australia under the IFR will be required to be equipped with GNSS.

This section provides information on aircraft navigation.


Surveillance technology is advancing from the legacy radar based solutions. To increase the area of Australia that is covered by surveillance, GNSS based Automatic Dependent Surveillance – Broadcast is being implemented. Another technology that is being employed for surveillance in some parts of Australia is Multi-Lateration, which is a system that makes use of the existing transponder installation in aircraft and a network of ground receivers to determine the aircraft position by triangulation.

Beginning on 12 December 2013 there will be a progressive implementation of ADS-B in Australia until 2 February 2017 when all aircraft operating under the IFR will be required to be equipped with 1090 MHz Extended Squitter ADS-B.
This section provides information on aircraft surveillance.

Resources and regulations

We have regulations and aircraft equipment mandates in place to support CNS/ATM. In December 2014, CAO 20.91 (Instructions and Directions for Performance-Based Navigation) and CAO 20.18 (Aircraft equipment – basic operational requirements) were revised and re-published. CAO 20.18 advises of the equipment (ADS-B and GNSS) mandates to be met between December 2013 and February 2017. These CAOs affect all IFR pilots and aircraft operating in Australia.

This section provides links to the regulations, ACs and other related guidance material.

CNS/ATM resource kit

Learn more about our new updated CNS/ATM resource kit due out in 2016.

CASA and Department of Defence safety agreements

CASA and the Department of Defence signed a subordinate agreement on the promotion of aviation safety and airworthiness in September 2016. The agreement compliments the existing primary agreement between the two agencies on safety and airworthiness.

The subordinate agreement provides for future collaboration between CASA and Defence, with the policy jointly developed for the safety oversight of civil operations into joint user and military airports. The agreement also meets recommendation 13 of the Government Response to the Aviation Safety Regulation Review.

Agreement on the promotion of aviation safety and airworthiness

Subordinate agreement on the promotion of aviation safety and airworthiness


For CNS/ATM queries email: cns@casa.gov.au, or phone 131 757 and request to speak to the CNS team.