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

Air Traffic Flow Management

The first stage of the Collaborative Decision Making (CDM) project replaced the Central Traffic Management System (CTMS) tool which services Sydney and Perth with an advanced Air Traffic Flow Management (ATFM) application capable of simultaneously managing traffic flows at multiple airports. This new application is called Harmony for ANSPs (Harmony). Harmony is used to run arrival Ground Delay Programs (GDP) for Sydney, Brisbane, Melbourne and Perth airports. In addition, a departure GDP is run for Perth Airport peak morning departures.

Ground Delay Programs

Harmony accepts real-time updates to schedule data, either via flight plan submission, airline day of operations changes to scheduled departure times, or ATC live data. As a consequence of accepting real-time updates, Harmony is able to display the most up-to-date demand/capacity information for any monitored airport, which in turn provides airlines, airports and ATC with an enhanced capability to predict traffic management issues. To maximise the capabilities of Harmony, it is important that all airspace users update their schedules on “day of operations” as soon as schedule changes become known.

All airlines intending to operate into a GDP airport are required to submit operating details into the Harmony system. Airlines upload a schedule directly into a web based interface, and smaller operators contact the Network Coordination Centre (NCC) who will enter their details into the system.

Aircraft and airport operators can view the GDP information for affected flights via web based access to the Harmony tool. User login to this service is managed by Airservices.

Compliance management

The established ATFM concept of operations and business rules acknowledge the importance of compliance with an established GDP to ensure optimum efficiency and balanced distribution of delays for all stakeholders. It is also acknowledged that, at times, there may be a need for flights to intentionally not comply with an assigned delay on the ground and absorb any remaining delay airborne (due to gate restrictions, etc.).

To ensure the balanced distribution of delays, GDP information will be made available to both Tower Air Traffic Control (ATC) positions and destination airport Flow Management positions.

This information will be used by ATC to advise flights when they are not complying with the GDP and, if necessary, take action to ensure compliant flights are not unfairly delayed by non-compliant flights. This will normally take the form of delaying non-compliant flights at the departure airport or during the en route or arrival phase of the flight.

More information on ATFM and GDPs is located in AIP ENR 1.9 and ERSA entries for Sydney, Brisbane, Melbourne and Perth Airports.


Specific documentation on ATFM procedures and Harmony is available on the ATFM documentation web page.


Aircraft Operators who operate a combined total of more than five regular flights per day into Sydney, Brisbane, Melbourne or Perth are required to have interactive access to Harmony.

Each Operator will, on a daily basis, be required to upload their schedules, as well as tactically manage their fleet to ensure the optimum usage of available landing slots at all airports subject to a traffic management initiative (TMI).

Pilots of unscheduled flights planning to operate into Sydney, Brisbane, Melbourne or Perth during the hours of a ground delay program are required to call the NCC on 1800 020 626, and Airport Coordination Australia (ACA) (02) 9313 5469 as appropriate prior to their flight to obtain a Calculated Off Blocks Time (COBT) for their departure. Refer to ATFM Pilot Briefing Paper Version 5 and Guide for Operations through Airports Subject to Slot Scheme and Ground Delay Programs for more information on this process.

Airport Operators will be assigned a passive read only access. This access will provide them with arrival and departure information for aircraft operating into and out of their airport.

Participants and Applications to Participate

Harmony web client access is provided to the following groups of users.

  • Aircraft Operators of regular services into Sydney, Brisbane, Melbourne and Perth airports
  • Airport Operators whose airport has regular services into Sydney, Brisbane, Melbourne and Perth airports
  • Other aviation groups who demonstrate a legitimate requirement for access.

Application for access to Harmony shall commence by providing limited details to, and shall include the following details:

  • Company name
  • Applicants full name and title
  • Phone number
  • Justification of requirement for Access.

Further information may be requested by the ATFM Operational Authority.

After initial review the following two documents will be forwarded for completion:

  • ATFM System Access User Guide
  • CDM Data Sharing Agreement

The registration form at the rear of the User Guide and the CDM Data Sharing Agreement must be completed and signed before system access is granted.

Training shall be provided to aircraft operators by ASA. Once this is completed and the aircraft operator has confirmed their company has completed in house training, access to the operational system shall be granted.

Once system access is granted, logins, passwords and the URL for access to Harmony shall be forwarded by the ATFM operational authority.

Further information is available from:

Airservices Network Coordination Centre
Phone: 1800 020 626