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ATS surveillance services

Operating requirements for ADS-B transmitters AIP ENR 1.1

Pilots of aircraft fitted with a serviceable ADS-B transmitter which has been confirmed suitable to receive ADS-B derived ATS surveillance services in Australia should activate the transmitter at all times during flight.

Aircraft equipped with ADS-B having an aircraft identification feature shall transmit the aircraft identification as specified in the flight notification or, when no flight notification has been filed, the aircraft registration.

Operation of transponders AIP ENR 1.6

Except as indicated below, ATS will assign a temporary discrete code for each  flight for aircraft operating in controlled airspace, and for aircraft participating  in Surveillance Information Service (SIS).

Unless otherwise advised by ATC, pilots of Mode 3A or Mode S transponder-equipped aircraft operating in Australian airspace must activate their transponders, and where a Mode C capability is also available it must be activated simultaneously with Mode 3A.

Pilots must ensure that transponders and ADS-B transmitters are activated and that altitude function is selected as:

  • primary radar coverage only exists within 50 nm of major airports and the remainder of the ATS surveillance system relies on SSR transponder and ADS-B transmitter information
  • TCAS relies on transponder information for its pilot alerting and collision avoidance functions.

When operating in Australian airspace, transponder-equipped aircraft must select and use codes in accordance with the following criteria:

Civil flights in Classes A, C and D airspace, or IFR flights in Class E airspace
Civil IFR flights in Class G airspace
Civil VFR flights in Class E or G airspace
Military flights in Classes A, C, D or E airspace
Military flights in Class G airspace
Civil flights not involved in special operations or SAR, operating in Class G airspace in excess of 15 nm offshore
Civil flights engaged in littoral surveillance
Ground testing by aircraft maintenance staff
Flights operating at aerodromes (in lieu of the first three of this list when assigned by ATC)
RPAS in all classes of airspace and when instructed to enable transponder.

Pilots of flights which will require a SIS and/or a clearance into controlled airspace, and for which a discrete code has already been coordinated, must select that code immediately prior to making their SIS/clearance request.

A pilot must not operate the IDENT pushbutton (shown in the picture below) unless requested to do so by ATC.

The IDENT pushbutton activates the special position indicator (SPI) function of the transponder.

A pilot departing from a radar-controlled aerodrome must leave the transponder selected to Standby until entering the departure runway, and on arrival select Standby or Off as soon as practicable after landing.

Transponder emergency codes AIP ENR 1.6

Pilots of aircraft encountering an emergency in flight, other than loss of two-way communications, should select code 7700 unless they have specific reason to believe that maintaining the assigned code would be the better course of action.



The pilot of an aircraft losing two-way communications must set the transponder  to code 7600.

A radar controller observing a 7600 code shall request the pilot to ‘squawk IDENT’ (which means to activate the SPI function). If the identification signal is received, further control of the aircraft will be continued using the identification transmission to acknowledge receipt of instructions issued.

If the identification is not received, the aircraft must continue with the transponder on code 7600 and follow radio failure procedures set out in the VFRG section emergency procedures-communications failure.

Radio communications procedures AIP ENR 1.6

Pilots requesting ATS surveillance services should address their request to the  ATS unit with which they are communicating.

Where an area approach Control Centre (AACC) is not established, the pilot will be advised the time or place to transfer to a control frequency.

Where an AACC is established, procedural and ATS surveillance services may be provided on a common frequency. The callsign identifies the service being provided, for example: ’… centre’, ’… approach’, ’…departures’.

Identification procedures AIP ENR 1.6

Before providing an ATS surveillance service there will be positive identification of the aircraft concerned. However, control services will not be provided until the aircraft is within controlled airspace.

Vectoring procedures AIP ENR 1.6

On receipt of heading instructions the pilot must, unless otherwise instructed, immediately commence a rate 1 turn, or the standard rate of turn for the aircraft type, and then maintain the heading given.

Aircraft will normally be vectored on routes along which the pilot can monitor navigation.

ATC are not permitted to vector special VFR flights, unless warranted by an emergency.

When an aircraft is given a vector which will take it off an established route, the pilot will be advised of the reason for the vector, unless it is self-evident.

When an aircraft reports unreliable directional instruments, the pilot will be asked, before being issued with manoeuvring instructions, to make all turns at an agreed rate and to carry out the instructions immediately on receipt.

When aircraft are being vectored, the controller will assign altitudes which allow for terrain clearance. However, in VMC by day, an aircraft may be permitted to arrange its own terrain clearance. In such instances the aircraft will be instructed to:

[Turn left (or right) heading (heading)] [climb (or descend) to (level) visual.

Pilots being vectored will be routinely advised of their position to enable pilot navigation in the event of radio or ATS surveillance system failure.

The interval between ATC transmissions will be kept short to enable the pilot to quickly recognise a communication failure. When aircraft are on headings that could infringe terrain clearance or separation standards, the intervals between transmissions will not exceed 30 seconds.

Before take-off, ATC may assign a heading for a departing aircraft to assume after take-off, followed by frequency change instructions if appropriate. Headings, other than those assigned for a standard radar SID, will only be issued for a visual departure by day in VMC.

Arriving aircraft may be vectored to:

  • establish for a radar or pilot-interpreted approach
  • a position from which a visual approach can be made
  • avoid areas of hazardous weather or severe turbulence
  • expedite traffic flow or conform to noise abatement requirements.

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New rules come into effect from 2 December 2021 that cover the general operating and flight rules. We are currently updating this guide to reflect the new rules. A new version will be available to download from 2 December.
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