Surveillance network and equipment

Surveillance network

Australia’s air traffic management system uses a network of different surveillance systems to detect and track aircraft. These include:

  • primary surveillance radars at major aerodromes
  • secondary surveillance radars (SSRs), either co-located with primary radars, or installed as stand-alone systems, for the busy air routes
  • automatic dependent surveillance-broadcast (ADS-B) receiver stations installed around Australia and at some offshore locations
  • multilateration systems, which use SSR and ADS-B signals to determine the position of aircraft (installed in Tasmania and in the Sydney basin)
  • advanced surface movement guidance and control systems (A-SMGCS) used to track aircraft taxiing or flying in the immediate vicinity of the airport (installed at Brisbane, Melbourne, Perth, and Sydney airports).

If you have any queries on the surveillance network, you can contact us by using our contact form.

Required surveillance equipment

Aircraft surveillance equipment must meet the requirements specified in Division 26.16 of the Part 91 Manual of Standards (MOS). These standards ensure compatibility with the surveillance network and enable collision detection and avoidance systems to operate effectively.

Unless otherwise directed by air traffic control (ATC), you must operate required surveillance equipment continuously during flight.

You must set the Mode A code on your transponder to the code assigned by ATC. If ATC has not assigned a Mode code, you must use the Mode A code appropriate to the type of flight and airspace you are operating in.

See the Aeronautical Information Publication (AIP) for details.

You must configure Mode S transponders and ADS-B equipment to transmit:

  • the allocated 24-bit address, and
  • the aircraft identification you entered in item 7 of the filed flight notification (you must transmit the aircraft registration if you haven’t filed a flight notification.)

Optional surveillance equipment for VFR aircraft

Section 26.68A of the Part 91 MOS allows several optional surveillance equipment configurations for VFR aircraft, including Electronic Conspicuity (EC) devices. These equipment configurations aim to enhance situational awareness by making the aircraft detectable by ADS-B receiving equipment (ADS-B IN) to pilots in other aircraft.

You can only carry or fit optional surveillance equipment if you have met any surveillance equipment requirements for the airspace you are operating in.

Flying without required surveillance equipment

Section GEN 1.5 in the Aeronautical Information Publication (AIP) provides more information about flying without required surveillance equipment.

Read the rules and regulations for CNS and ATM for information about:

  • written authorisation for flight without required surveillance equipment
  • exemptions against fitment requirements.

Notes for surveillance equipment

Following is useful information about surveillance equipment:

(E)TSO C129 GPS equipment

Some old (E)TSO C129 GPS systems, while suitable for performance-based navigation (PBN), will not meet the requirements for ADS-B. Later versions that output the GPS position horizontal protection limit (HPL) and incorporate fault detection and exclusion (FDE) may meet the requirements. Please refer to Section 26.71 of the Part 91 MOS for the specific requirements.

Purchasing aircraft with ADS-B from the US

We have authorised Mode S Extended Squitter as the ADS-B system for use in Australia. Mode S Extended Squitter operates on a frequency of 1090 MHz and is commonly referred to as either:

  • 1090 MHz Extended Squitter
  • 1090 MHz ES.

The US Federal Aviation Administration (FAA) allows aircraft that operate below FL 180 in the US to be fitted with an ADS-B system known as Universal Access Transceiver (UAT). UAT operates on a frequency of 978 MHz. It does not meet the Australian ADS-B requirements.

If you are purchasing an aircraft from the US, confirm whether any ADS-B equipment installed on the aircraft is:

  • Mode S Extended Squitter
  • UAT.

Electronic conspicuity (EC) devices

An electronic conspicuity (EC) device is an ADS-B system designed for use on light aircraft. It broadcasts information that enables the aircraft to be detected by other airspace users with equipment that can receive and process the information (ADS-B IN).

You must not operate an EC device at the same time as a Mode S transponder which is transmitting ADS-B messages. This is to avoid interference to the two devices caused by unsynchronised transmissions and prevent the aircraft from broadcasting inconsistent information.

ADS-B transmissions from EC devices will generally not be visible on air traffic control screens.

If you have any questions or would like to report an issue with an EC device, you can contact us using our online form.

EC device declaration of capability and conformance

You can only use an EC device on an aircraft if the device has a valid declaration of capability and conformance. Manufacturers may submit a declaration by using the following form:

We will list valid declarations from manufacturers in the table below. We will contact the manufacturer if there is an issue with the declaration or EC device.

Record number Manufacturer Model Issue number Category


uAvionix Corporation

SkyEcho 2

0 (original product)



uAvionix Corporation


0 (original)

Basic / transmit only


Manufacturers must submit a new declaration of capability and conformance if they make certain changes to EC devices.

For details on how to submit a new declaration read:

EC device standards

Section 26.72C of the Part 91 MOS specifies the minimum technical requirements for EC devices. EC devices manufactured or marketed for use in Australia need to meet these requirements.

You can find further details on EC devices in:

24-bit addresses for EC devices on unregistered aircraft

Contact the civil aircraft registrar to obtain a 24-bit address if you plan to use an EC device on an unregistered aircraft.

You will need to provide:

  • your contact details,
  • details of the aircraft you propose to use the device on, and
  • the device's make, model, and serial number.

We will allocate a 24-bit address to the EC device if it has a valid declaration of capability and conformance. If you receive a 24-bit address, you may use the device on the nominated unregistered aircraft without re-programming the 24-bit address.

Note that CASA has guidelines for the use of EC devices on remotely piloted aircraft systems (RPAS).

24-bit addresses for EC devices on registered aircraft

We allocate a 24-bit address to each registered aircraft. You must program this 24-bit aircraft address into the EC device if you are using it on a registered aircraft.

Contact the civil aircraft registrar if you don’t know the 24-bit address of your aircraft.

If you have a portable EC device and need to move it to another registered aircraft, you must reprogram it with the 24-bit address of the aircraft you are using.

Selling or disposing of an EC device

If you sell or dispose of your EC device, you must clear the 24-bit address from the device before the sale.

Last updated:
8 Dec 2022
Online version available at:
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