Calendar Explanation

Slot Historical Listing (SHL)

All slot coordinators of level 3 airports will send airlines a Slot Historical Listing. A ‘historic’ slot is a slot that has been operated 80% of the previous adjacent season. For example, an airline must operate 80% of a series in the previous Winter season to gain historic for the next Winter season.

What Makes a Historic Slot?

  • A series of 5 or more flights that has operated 80% of the time
  • A slot on a particular day, at a particular time eg every Monday at 0800z

Initial Submission

All airlines are to submit their initial filing for the upcoming season 35 days prior to the Slot Conference. This is mandatory for all airlines operating into a level 2 or 3 airports.

Slot Allocation Listing (SAL)

The slot allocation listing is sent by the coordinator to the airline 14 days prior to the slot conference. This is a listing of all confirmation and offers of slot for the upcoming scheduling season.

Between the SAL and the Slot Conference, the only communication airlines and coordinators can undertake, is discussion of strategic planning and slot change requests that do not impact the capacity of the airport. These include: flight number changes, some route changes, equipment downgrades and cancellations of slots. New slot requests can be submitted, but will be responded to on the first day of the conference.

Slot Conference (SC)

The slot conference occurs twice a year, once for the Winter season (in June) and once for the Summer season (in November). Slot conferences involve all level two and level three airport coordinators and airlines. The conferences are set up to provide a platform for the airlines to work directly with coordinators to work out any slot issues they have and to discuss airport constraints and strategies. As you cannot judge one airport in isolation, a change to one port has a ‘knock on’ effect to the rest of an airline’s network and therefore the conference provides an opportunity to see different coordinators simultaneously to work out problems and leave with a firm schedule.

Slot Return Deadline

The slot return deadline provides airlines an opportunity to hand back any unwanted slots that they no longer wish to operate in the upcoming season. The slot return deadline is the 15th of August for the Winter season and the 15th of January for the Summer season.

Use it or lose it Calculation

All slots that airlines are holding at the 31st of August (for Winter) and the 31st of January (for Summer) will be included in the calculation for historic precedence. If an airline cancels a slot, or series of slots after the 31st of August/January this will be calculated in the historic’s for the next adjacent season. If an airlines knows that they will not operate a slot, or series of slots it is advisable to cancel these before the use it or lose it calculation. Airlines that experience events beyond their control may receive dispensation for historic calculation, these events are not limited to but may include, industrial action, weather events such as volcanoes, closure of airports or airspace (IATA WSG, 2014).