Slot Monitoring


1. The Purpose of Slot Monitoring

Pursuant to EU Reg 793/2004, Art 4, par 6, the schedule facilitator shall monitor the conformity of the air carriers' operations with the schedules recommended to them and the coordinator shall monitor the conformity of air carriers' operations with the slots allocated to them. The process of slot monitoring aims to improve performance according to allocated slots or recommended schedules by discovering and combating misuse of slots as described in EEC Reg 793/2004 and IATA’s Worldwide Slot Guidelines.

2. HSCA Principles

Establish objective, transparent and non-discriminatory criteria.

Engage in conversation with air carriers with the aim of improving performance or taking corrective actions.

Identify the intentional misuses of slots.

3. Definitions (in alphabetical order)

Air Carrier: An air transport undertaking entity, holding a valid operating license or equivalent at the latest on 31 January for the following summer season or on 31 August for the following winter season. The definition of Air Carrier shall also include business aviation operators, when they operate according to a schedule; the definition shall also include all civil aircraft operators.

Beyond its reasonable control, this could include:

Weather conditions.

Industrial actions.

Air traffic control regulations.

Technical issues.

Force Majeure events as interpreted in EEC Reg. 793/2004 and the WSG.


It is the Air Carrier’s responsibility to demonstrate that discrepancies between slot times and operated times were beyond its control.

Intentionally: Any case of landing or take-off scheduled, planned and operated with different characteristics than the allocated slot that is not subject to operational disruptions.

Repeatedly: Twice or morerecurring discrepancies during the current IATA scheduling season on a particular scheduled or non-scheduled series of slots operated by an air carrier to or from the airport in question.

Significantly different time: Any difference between the intended (scheduled) landing or take-off time and the allocated slot time, will be regarded as a ‘’significantly different time’’.

Significantly different way: Carriers will be considered as operating in significantly different way when

Operating with an aircraft of bigger passengers’ capacity than the aircraft of the allocated slot.

Operating with false indication of Service Type in the allocated slots that affects airport parameters.

Operating with intentionally false indication of route (e.g. SCHENGEN -NON-SCHENGEN) that affects airport parameters.

Tolerance: Operational variations between allocated and actual operated times when no extraordinary conditions, beyond the airlines’ control, are present.

4. Types of slot misuse 

The most common types of misuse are: 

Operating according to published schedule time that differs from the allocated slot time (OFFSLOT)

Using a slot in a significantly different way (DIF) than the allocated slot.

Operating a flight without an allocated slot (GOSHOWS) with the exception of flights as described in the latest iteration of AIP Greece article

All VFR flights.

Flights which are diverted to an alternative aerodrome for technical or meteorological reasons.

Flights undertaken for humanitarian reasons.

Flights on search and rescue missions.

Sanitary flights.

State flights.

Military flights.

Failing to operate a slot allocated by the coordinator without cancelling it in advance that does not fall in the scope of EEC Reg 793/2004 Article 10 par.4. (NOSHOWS).



 If a discrepancy, as described above, is deemed as intentional, the air carrier will be liable for sanctions.


5. Monitoring Procedures and Methods 

Before the Date of Operation

Coordinators shall discover and prevent probable slot misuse by undertaking conformity checks before the date of operation, where possible. The following data sources (indicatively but not exhaustively) may be used to detect inconsistencies:

Data of the airport concerned or from another airport that is part of the particular service (e.g. cooperation with other countries’ coordinators).

Published schedule data (websites, CRS, timetables, brochures, tickets, etc.).

ATC flight plans.

Any other relevant source.


In cases where inconsistencies are detected the coordinator shall establish and maintain contact with the airline.

After the Date of Operation

After the date of operation, Coordinators shall compile a database of actual operations compared to allocated slots, updated on a weekly basis. This data will be analysed to detect inconsistencies and identify possible slot misuse. For this comparison, the coordinator will use data provided by the airport operator and / or any other data sources (e.g. ATC).

Coordinators shall 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.

Distinguish repeated (possibly intentional) OFFSLOT operations from random operational variations (Change of A/C due AOG, heavy rotational delays etc.) and check whether the deviation is a result of an obvious operational disruption.

Check for evidence of intentional slot misuse such as published schedule time different than the allocated slot time, or operations closer to the requested time than the allocated slot time.


  If discrepancies are discovered in the use of allocated slots, the coordinator shall contact the air carrier concerned in a timely manner. A reply must be provided within five (5) business days from the receipt of this information. If deemed necessary, the carrier must proceed to corrective actions. 

If the case is resolved through discussion with the air carrier, the Coordinator shall continue to monitor these operations. In those cases where resolution is not met via discussion, the Coordinator shall take further appropriate action.


General Actions and Sanctions 

Issue a notification or warning. 

Request for corrective actions.

Withdrawal of the remainder of the series of slots under certain criteria and the provisions of EEC Reg. 793/2004.

Loss of historic eligibility for next equivalent season.

Lower priority in the allocation of slots at the specific airport for the next equivalent season.

Temporary access restrictions in provided online services for Greek Airports if abuse of the system is detected.

Report the case to the Hellenic Civil Aviation for any further action needed according to the latest iteration of AIP Greece.