Scheduling FAQ

Schedules Conferences are held twice yearly. The conference dealing with northern winter schedules is held in June and the conference held in November deals with the northern summer schedules for the following year.

Since 1947, under the auspices of IATA, airlines have met regularly to discuss schedules planned for the following season in order to improve interline connections and handling arrangements.

Primarily through bilateral discussions, they voluntarily adjusted their schedules where it was in their mutual interest to do so. Their main objective was to return home with firm schedules that triggered the various preparations that were needed to operate them.

With the onset of congestion at a few major airports in the early 1960s, the scope of the schedule discussions was broadened to cover the adjustments needed to reduce anticipated delays to an acceptable level.

In instances where airport services that were planned during certain periods exceeded what the airport could accommodate, some services would have to be moved, usually with some economic penalty. Over the years, a consensus developed as to which services should be moved, in fairness to all those who were planning to operate during the period.

The recommended procedures and priorities for such schedule adjustments are contained in the IATA Worldwide Scheduling Guidelines first issued in 1976

Any airline that is licensed to operate air services or that has applied for a license to operate air services, Also coordinators from slot-coordinated airports (Level 3 airports) provided they have been approved by their government, and schedules facilitators from schedules-facilitated airports (Level 2 airports) provided they have been appointed by the appropriate authority.

Conference policy permits only airlines, coordinators and schedules facilitators to attend conferences. However, in the case of government officials, airport operators or their representatives or any other non-airline representatives, exceptions may be granted by IATA for the purpose of familiarization and normally for one conference only. Non-airline personnel wishing to be invited to a Schedules Conference should send their request to IATA Management at least 30 days in advance of the Conference they wish to attend.

A participant can be accredited on behalf of more than one company/ agency. Where coordination is performed by a national carrier, a participant can be accredited as both an airline representative and a coordinator.

In the context of mergers, subsidiaries, service contracts or alliances: One registration is required for each AOC / coordination agency. A participant can be accredited on behalf of more than one company/ agency

Venue criteria can be found in the Schedules Conference section. Completed forms should be e-mailed to the attention of Carolyn Bourke, Conference Manager, IATA Conferences & Exhibitions Department.

Only IATA Member airlines are eligible for participation in SPWG. Members of the SPWG are appointed by the Director General of IATA. Individuals interested in becoming members of the SPWG should send a curriculum vitae together with a letter of support from the CEO of his/her organization to the
IATA Director Passenger
IATA Centre, Route de l'Aéroport 33, P.O.B. 416
CH-1215 Geneva 15 Airport, Switzerland.

The Joint Scheduling Advisory Group is an IATA forum comprised of seven airline members and seven coordinators. The coordinator members of JSAG are elected by the coordinator community from the Worldwide Airport Coordinators Group (WWACG). The seven IATA airline members are appointed by the IATA Director-General from the membership of the Scheduling Policy Working Group (SPWG).

Subscribe to the IATA Standard Schedules Information Manual (SSIM).

Appendix F of the IATA Standard Schedules Information Manual (SSIM) provides UTC Standard and Daylight Saving Time-Local Time variations for each country where regular scheduled services operate.

• UTC (Appendix F) notifications are available on SkedLink for all SISC participants
• UTC notifications are distributed to subscribers of the SSIM

For the purpose of Resolution 765, in a passenger context, a Minimum Connecting time (MCT) interval is defined as the shortest time interval required in order to transfer a passenger and his luggage from one flight to a connecting flight, in a specific location or metropolitan area. In a cargo context, the MCT can be defined as the shortest time interval required in order to transfer cargo shipment from one flight to a connecting flight.

MCT intervals are also referred to as ‘official’ or ‘standard’ MCTs. Bilateral MCT agreements, and online connecting time intervals established by a carrier that differ from the industry MCTs, are known as ‘MCT exceptions’.

MCTs must be observed by all ticketing and reservations outlets all over the world and also are used as input for automated reservations systems.

Establishment of and changes or exceptions to standard MCTs are governed by the provisions of IATA Resolution 765 Official MCTs are determined by the airport local MCT group, which consist of scheduled airlines and railways serving an airport, or if there is no such a group, by the Airport Operating Committee (AOC). Once IATA has been informed by such a group of the setting of, or changes to, existing official MCTs, IATA notifies the Scheduling community (including IATA partners such as CRS/GDS/schedule aggregators) of the changes by posting them on the IATA SkedLink.

MCT industry notifications are available on SkedLink for all Airline professionals

Official MCTs are used by default. Airlines may decide to deviate from the official MCT in a given airport by publishing a MCT exception. When two airlines are involved, connecting time exceptions, if required, are usually established on a bi-lateral basis. These exceptions to MCTs are generally less than the airport official MCTs and are basically marketing agreement between airlines, or exception within an airline’s own air service. It is the airline's responsibility to set realistic connecting times to allow for connections of passengers and baggage. Carrier exceptions need to be filed with the main data aggregators, as well as with the GDS when applicable.

The Local Airport MCT Group Chairman shall communicate MCT changes to the IATA Schedules Service Department by email.

MCT tables are available from the Schedule reference Service (SRS)

Copies of the current edition of the IATA Worldwide Scheduling Guidelines are available in pdf format and can be downloaded free-of-charge from the IATA Scheduling website

The northern summer scheduling season begins on the date of Daylight Saving Time (DST) introduction in European Union countries, which currently always takes place on the last Sunday in March. The northern winter scheduling season commences on the date Daylight Saving Time (DST) ends in European Union countries, which currently always takes place on the last Sunday in October.

Annex 3 of the Worldwide Scheduling Guidelines contains a complete list of schedules facilitated (Level 2) and coordinated (Level 3) airports along with the TTY and e-mail contacts for the schedules facilitators/coordinators responsible for each airport.

Airlines with traffic rights permitting them to operate to a Level 1 airport should notify their appointed handling agent and the relevant airport managing body, or the data collecting agent if one has been appointed, of their planned schedule.

Airlines operating to, or intending to operate to, a Schedules Facilitated (Level 2) airport must submit their proposed schedules to the Schedules Facilitator of the airport concerned. Submissions must be made using a Schedule Movement Advice (SMA) message. For complete details on SMA message format please refer to Chapter 6 of the Standard Schedules Information Manual (SSIM). Addresses to which SMAs should be sent are shown in Annex 3 of the IATA Worldwide Scheduling Guidelines (WSG).

Airlines operating to, or intending to operate to, a Coordinated (Level 3) airport must submit their proposed schedules to the Coordinator of the airport concerned. Submissions must be made using a Schedule Clearance Request (SCR) message. For complete details on SCR message format please refer to Chapter 6 of the Standard Schedules Information Manual (SSIM). Addresses to which SCRs should be sent are shown in Annex 3 of the IATA Worldwide Scheduling Guidelines (WSG).

A slot is defined as the scheduled time of arrival or departure available for allocation by, or as allocated by, a coordinator for an aircraft movement on a specific date at a coordinated airport.

The Slot Historical and Non-Historical Allocation Lists (SHLs) must be distributed for each airport, as soon as the historics have been determined by the coordinator, but not later than:

the third Monday in April for what is on record as historical slots, as actually operated in the preceding Northern Winter scheduling period;
the third Monday in September for what is on record as historical slots, as actually operated in the current Northern Summer scheduling period up to that time.
It must be noted that information given to airlines prior to the end of the Summer scheduling period must be regarded as provisional until the season is completed.

Airlines must submit their Slot Clearance Requests (SCRs) to the appropriate Coordinators and their Schedule Movement Advices (SMAs) to the appropriate Schedules Facilitators by 23:59 UTC on the 30th day prior to the start of the Schedules Conference.

Coordinators must inform relevant airline delegations of the status of all their requested slots as soon as possible but not later than 23:59 UTC on the 9th day prior to the start of each Schedules Conference using the Slot Preliminary Allocation List (SAL) message.

The airline must immediately advise the coordinator and return any slots it knows it will not use. In particular these slots must be returned no later than 31 January for the next Northern Summer scheduling period and no later than 31 August for the next Northern Winter scheduling period.

A series of slots is defined as at least five slots having been requested by an airline at an airport for the same time on the same day of the week regularly in the same scheduling period and allocated in the same way, or if that is not possible, allocated at approximately the same time. The expression 'same time' in this context means within the same coordination parameters.

Both terms are intertwined and refer to a requirement for airlines to operate at least 80% of their allocated slots to their coordinated timings or face the possible loss of historical precedence for those particular slots in the next equivalent scheduling season.

Conversely, if an airline fails to operate no more than 20% of their allocated slots to their coordinated timings, the airline will retain historical precedence for its slots in the next equivalent season.

A 'new entrant' is defined as an airline requesting a series of slots at an airport on any day, where if the airline's request was accepted, it would hold fewer than five slots at that airport on that day.

Only airlines can be eligible for new entrant status. Of the slots contained within the slot pool at the initial allocation, 50% must be allocated to new entrants, unless requests by new entrants are less than 50%.

The coordinator shall treat requests of new entrants and other airlines fairly, in accordance with coordination periods of each scheduling day. Other criteria for allocating slots from the pool are secondary to this criterion. An airline’s slot request should have new entrant status provided that the request, if accepted, would result in the airline holding fewer than five slots at that airport on that day.

An airline must not claim new entrant status if it intends to operate on an ad hoc basis. A new entrant, who has been offered slots within one hour before or after the time requested, but has not accepted this offer, will not retain new entrant status for that scheduling period.

Airlines shall inform the coordinator, at the time of the request for allocation, whether it would benefit from the status of new entrant in respect of the requested slot. If new entrants are dissatisfied with the response to their slot request, they may ask for a meeting of the appropriate coordination committee to consider the situation.

In the interests of fairness and transparency, coordinators must make available, upon request, the following information for review by all interested parties:

(a) Historical slots by airline and chronologically for all airlines.
(b) Requested slots (initial submissions) by airline and chronologically for all airlines.
(c) All allocated slots, and outstanding slot requests, by airline and chronologically for all airlines.
(d) Remaining slots available.
(e) Comparisons between (a) and (c) above by time interval coordinated and by airline.
(f) Full details of the constraints being used in coordination.
(g) Full details of the criteria being used in the allocation of slots.

From the WSG perspective a transfer of slots is allowed with the following stipulations:

(a) Slots may only be transferred to another airline that is serving or planning to serve the same airport.
(b) The slots being transferred must have been operated for two equivalent scheduling periods.
(c) These types of transfers should involve the airport coordinator for final confirmation.
Further information can be found in section 6.10.2 of the WSG.