Schedule Coordination Conferences, in which any airline may participate if registered in a State that is eligible for membership in ICAO, are held twice each year – about four months before the start of the summer and winter scheduling seasons that are to be discussed. Airport capacity limitations applicable for the season under discussion are declared before the Conferences by the appropriate authorities in consultation with airlines.
About three weeks before each Conference, airlines provide Coordinators with schedule clearance requests for the arrival and departure times required at the airports concerned.
The Coordinator collates this information and identifies periods in which slot requests exceed declared airport capacities. Airlines with requests that are regarded as having a lower priority are offered the nearest alternative timings available at the beginning of each Conference, and demand is thus reduced to match capacity.
During the Conference, schedules are adjusted mainly through bilateral discussions between airlines and Coordinators regarding alternatives offered, or between airlines to exchange slots offered or accepted. A schedule change at one airport must affect one or more other airports.
Because all Coordinators attend the Conference, it provides the best forum in which all such repercussive changes can be quickly and efficiently processed. Thus, airlines can leave the Conference with firm schedules which they consider to be the best compromise between what is desired and what is available.
The entire process is based on consensus and aims to be flexible, fair and open. It is very seldom that airlines leave the Conference believing that the results have been inequitable.