Airservices is Australia's air navigation service provider - we provide air traffic control, aviation rescue and fire fighting and air navigation services.

Flight number call-signs

Flight number call-signs (FNC) are an ICAO approved type of aircraft radiotelephony call-sign. ICAO information on callsigns may be found in ICAO Annex 10 Volume 2 and ICAO Doc 8585. Australian Aeronautical Information Publication (AIP) provides rules for aircraft call-signs at GEN 3.4 paragraphs 4.15 to 4.24.

The designator and radiotelephony call-sign are used for flight planning and radio communication purposes only.

Airservices manages flight number callsign allocation for Australian aircraft operating agencies, aeronautical authorities and services.

Three types of call-signs are available:

  • Australian two letter (for domestic operations)
  • ICAO three letter (for international operations)
  • Special task (for operations such as police, fire and ambulance).

FNC are allocated where use will provide a benefit to the air traffic services system. Any benefit is weighed against the risk that improper use of call-signs or call-sign confusion can result in pilots executing a clearance intended for another aircraft.

The process of application and approval involves:

  • the selection of proposed designators and call-signs by the aircraft operating agency
  • assessment of aircraft operation suitability for the allocation of a FNC
  • assessment of safety implications (including callsign similarity risks and human factors)
  • consultation with Air Traffic Control (both civil and Defence)
  • application to ICAO (three letter only).

Once a FNC has been allocated, aircraft operating agencies will determine the flight numbers to be used in accordance with the guidance material found in AIP GEN 3.4 para 4.17. Operators must remain vigilant for the development of potential callsign confusion risks with their own and other operators’ call-signs.

Flight Number Callsign (FNC) Designators – Information and Application (PDF 639kb)
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Requests for approval to use flight number call-signs, or for more information, should be directed to:

ATS Integrity
Operations Standards and Assurance, Airservices Australia
GPO Box 367, CANBERRA ACT 2601