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Online Coordination

Slot Performance Monitoring


1. PURPOSE                                                                       EUACA

This EUACA Slot Guideline (EUSG) deals with slot performance monitoring by coordinators to ensure conformity between actual aircraft operations and the allocated slots. It also deals with data quality monitoring by schedules facilitators. Though linked, slot performance monitoring is distinct from the determination of historics and application of the use-it-or-lose-it rule (the 80/20 rule) – see also EUSG Determination of Historics.
The objectives of slot performance monitoring are to:
- Ensure adherence to allocated slots within normal operating tolerances
- Identify any instances of intentional misuse of allocated slots
- Prevent operations at a coordinated airport without an allocated slot
- Encourage the timely return of unwanted slots to the pool for reallocation


EU Slot Regulation No.95/93 (amended)

- Article 4(6) – duty to monitor use of slots
- Article 5(1) – role of the Coordination Committee to advise on methods of monitoring the use of slots
- Article 7(1) – duty of air carriers and other aircraft operators to provide requested information
- Article 7(3) – duty to exchange information
- Article 14(4) – withdraw slots for repeated and intentional slot misuse
- Article 14(5) – sanctions against slot misuse
- Article 14(6) – withdraw slots not being used

IATA Worldwide Slot Guidelines

- Section 1.7 and 7.1 – Key Principles of Slot Allocation
- Section 8.9 – Intentional Misuse of Slots


Slot monitoring is a continuous process that:
- uses objective, transparent and non-discriminatory criteria
- should be adapted to the specific needs of the airport and types of traffic
- should be timely and simple to calculate and administer
- follows advice given by the Coordination or Slot Performance Committee


3.1 Before the Date of Operation

Coordinators should seek to prevent slot misuse by undertaking conformity checks before the date of operation, where possible. The following data sources may be used to detect inconsistencies:
- published schedule data (websites, CRS, timetables, brochures, tickets)
- airport or ground handling data of the airport concerned or at the other end of the route (e.g. from an A-CDM system)
- EUACA combined database
- ATC flight plan
Coordinators should check for following types of inconsistencies:
- intention to operate with no corresponding slot
- slot held with no intention to operate
- intention to operate at a time different than the allocated slot
- intention to use a slot in a significantly different way than allocated
Having detected a discrepancy, the Coordinator should contact the aircraft operator concerned and ask for an explanation and corrective action in order to prevent misuse.
Schedules Facilitators should perform similar checks to ensure that air carriers or other aircraft operators intend to operate in conformity with the schedules recommended to them, or have advised the Schedules Facilitator of their inability to accept a voluntary schedule adjustment.

3.2 After the Date of Operation

After the date of operation, Coordinators should compile a database of actual operations compared with allocated slots, updated on a regular basis (e.g. weekly). These data should be analysed to detect inconsistencies and identify potential slot misuse. These consistency checks should be carried out in a timely manner. Analytical methods with supporting software tools should be used to facilitate the comparison.
For this comparison, the Coordinator should use data provided by the airport operator or other data source (e.g. ATC) with actual arrival and departure times.
As slot times are on/off block times, actual on/off block times should be used if available. If only runway landing and takeoff times are available, then appropriate taxi time assumptions must be applied.
Coordinators should check for inconsistencies in the use of slots, such as:

- operations with no corresponding slot

- slot held but not operated

- operations at a time different than the allocated slot

- use of a slot in a significantly different way than allocated (e.g. use of a larger
aircraft in breach of terminal or stand capacities).

- where applicable, flights operated in curfew or other restricted operations
periods without holding a valid airport slot for that period (e.g. night period)

Coordinators should avoid seeking unnecessary explanations from aircraft operators of minor operational deviations. In analysing the data, the Coordinator should undertake checks, such as:
- apply a reasonable tolerance for time differences to filter potential slot misuse from normal operational variability
- distinguish repeated (possibly intentional) off slot operations from random operational deviations
- check whether the deviation is a result of an obvious operational disruption (e.g. known events of extreme weather, strikes, etc). The Monitoring Events log on the EUACA website may be used for this purpose
- check for evidence of intentional slot misuse such as published times different than the allocated slot time, or operations closer to the initially requested time than the allocated slot time
- check whether the scheduled block time or turnaround time appears appropriate for the route and aircraft type
- check whether the scheduled turnaround time of the aircraft operator is realistic in the light of its actual operations

3.3 Follow-up Action

Where there is evidence of a significant discrepancy in the use of slots and/or apparent evidence of intentional slot misuse, the Coordinator should contact the aircraft operator concerned and request an explanation (setting a reasonable deadline for response), and to take corrective action where necessary.
Coordinators should try to identify slot performance issues as soon as possible and contact the aircraft operator concerned in a timely manner, giving the aircraft operator an opportunity to take corrective action during the current season.
For operations without a slot, Coordinators should check whether the reasons invoked by the operators to be exempted from slot allocation are valid (e.g. real diversion, head of state flight, ambulance/humanitarian flight).
If an adequate explanation is provided and/or appropriate corrective action is taken, the Coordinator should continue to monitor the situation.
Where there is evidence of intentional slot misuse or if no adequate explanation is provided, the Coordinator may take further appropriate action.
When deciding upon any further action, in accordance with the EU Regulation and national law, the responsible authority should take into account:

- if it is a first occurrence of an ad hoc operation (airline or GA/BA)
- if it is a repeated occurrence of an ad hoc operation (airline or GA/BA)
- if it is a first or single occurrence as part of a series of slots
- if it is a repeated occurrence as part of a series of slots
- the severity of the discrepancy
- if it was likely to cause prejudice to the airport or ATC operations
- the appropriate monitoring guidelines developed by the relevant Coordination Committee or Slot Performance Committee

The actions the Coordinator may take depend on the seriousness and/or continuation of the abuse, as well as national law.
Possible actions to deal with slot misuse are:

- issue a (first) warning
- request for corrective action
- summoning before the Coordination or Slot Performance Committee
- lower priority in the allocation of slots
- loss of historic precedence and/or withdrawal of that series of slots for the rest of the season (EU Slot Regulation Article 14.4)
- application of financial sanctions by the relevant authority, dependent on
national law (EU Slot Regulation Article 14.5)

3.4 Continuing Poor Slot Performance and Intentionality

The sanctions of EU Slot Regulation Article 14.4 (withdrawal of slots) and 14.5 (financial sanctions) can be only applied in instances of intentional slot misuse.
There are circumstances where poor slot performance is initially not deemed intentional, but may be considered intentional in future if the aircraft operator
concerned does not take reasonable corrective action.
Common examples are planned block times or turnaround times which cannot be reliably achieved in practice, or unrealistic planned aircraft utilisation leading to
poor slot performance. In such circumstances, the aircraft operator should be given the opportunity to take appropriate corrective action. However, if they do not do so then the
continued poor slot performance should be considered intentional slot misuse.

3.5 Slot Performance and the Application of the Use-it-or-Lose-it Rule

The application of the use-it-or-lose-it rule must be based on the non-utilisation of slots in a series which is either:
- a cancellation made after the relevant 31 January / 31 August deadline date
- a failure to operate without cancelling in advance unless such non-utilisation can be justified in accordance with EU Slot Regulation Article 10.4.

Aircraft operators should not be penalised for on-the-day operational delays in the application of the 80/20 rule (i.e. if the flight operates late but on the same day then it should count as ‘used’ for the 80/20 calculation).
Only if an aircraft operator intentionally operates at a significantly different time or uses slots in a significantly different way than allocated, then the appropriate sanctions are loss of historic precedence and/or withdrawal of slots under EU Slot Regulation Article 14.4 and/or financial sanctions under Article 14.5, not in the application of the use-it-or-lose rule under Article 8.2 and 10.2.


Following Coordinators/Schedules Facilitators have indicated that these guidelines or standards are not fully applied at all or some of the airports they currently manage. In order to get more detailed information about the differences and the reasons thereof, please visit the concerned Coordinator/Schedules Facilitator website.



Adopted Fully OR Exceptions applied


Austria (AT)

Adopted Fully

Belgium (BE)

Adopted Fully

Bulgaria (BG)

Adopted Fully

Croatia (HR)

Adopted Fully

Cyprus (CY)

Adopted Fully

Czech Republic (CZ)

Adopted Fully

Denmark (DK)

Adopted Fully

Faroe Islands (FO)

Adopted Fully

Finland (FI)

Adopted Fully

France (FR)

Adopted Fully

Germany (DE)

Adopted Fully

Greece (GR)

Adopted Fully

Hungary (HU)

Adopted Fully

Iceland (IS)

Adopted Fully

Ireland (IE)

Adopted Fully

Italy (IT)

Adopted Fully

Malta (MT)

Adopted Fully

Netherlands (NL)

Adopted Fully

Norway (NO)

Adopted Fully

Poland (PL)

Adopted Fully

Portugal (PT)

Adopted Fully

Spain (ES)

Adopted Fully

Sweden (SE)

Adopted Fully

Switzerland (CH)

Adopted Fully

United Kingdom (GB)

Adopted Fully

 Taken from EUACA's EUSG Nr 1 - Slot Performance Monitoring_15092013 (endorsed in EUACA-70)