Analytic Flying

Analytic Flying

How constrained are Sydney Airport's slots?

New insights from Sydney's first public Initial Coordination Report

Aug 06, 2025
∙ Paid

Earlier this year, the management of Sydney Airport’s slots was transferred from Airport Coordination Australia (ACA) to Airport Coordination Limited (ACL). While the names and acronyms are similar enough to be confusing, they are entirely separate entities, with the latter an international entity famous for managing and allocating London Heathrow’s slots.

While the management and allocation of Sydney’s slots has moved to ACL, there have been no meaningful changes in Sydney’s slot system including capacity and slot allocation rules, including the use-it-or-lose-it rule that allows incumbent slot holders to retain a slot provided they utilised it 80% of the time during the preceding season.

ACL is a UK company that was established in the early 1990s to manage slot allocations at the UK’s major airports, specifically London Heathrow. ACL is an independent not for profit company. It has grown to manage slots at 78 airports in 12 countries and is managed by a well-regarded professional staff. Their work is overseen by a board of directors that includes 11 directors:

  • 4 independent directors including the chair

  • 2 executive directors including the CEO and CFO

  • 5 airlines (BA, EasyJet, Jet2, TUI and Virgin Atlantic)

A critique of the board structure is that they represent UK interests. All independent directors are British, while the airline representation on the board reflects the major UK domiciles airlines. Nevertheless, ACL are simply the administrator and individual airports and/or country authorities maintain responsibility for establishing airport capacity including publishing capacity declarations, setting slot rules including slot retention and allocation rules, establishing slot committees, and establishing dispute resolution mechanisms.

There are many similarities between ACL and ACA. While not the same size and scale, ACA was established in 1997, initially to manage Sydney’s slots, and has since grown to manage slots at 7 other airports in Australia (Adelaide, Brisbane, Cairns, Darwin, Gold Coast, Melbourne and Perth) and two foreign customers (Manila and Port Moresby). Its board includes Qantas, Virgin Australia, the Regional Aviation Association of Australia and Sydney Airport, in addition to an independent chair.

Not all airports are slot constrained and slots are an important part of planning and resource allocation. This is evident as of the 78 airports that ACL manage, only 21 are “level 3” airports, while 27 and 30 are level 2 and 1 airports, respectively.

However, one area of meaningful change is with regards to transparency as ACL will now public regular reports, like they do for other airports they manage. Specifically, this includes the Initial Coordination Report which shows slot allocations for the forthcoming season by airline. The Initial Coordination Report provides a macro-level snapshot, for example, showing the number of slots allocated to each airline, but also the number of slots retained and slot, and the applications for new slots that were successful and unsuccessful. However, it doesn’t show specific timings, nevertheless it’s still a substantial improvement in transparency and should be acknowledged.

Notably, the Initial Coordination Report doesn’t segregate the Permanent Regional Service Series (PRSS) slots. PRSS slots are those that are ring fenced for NSW regional services, although these are detailed in a seperate publication.

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