Slot times at coordinated airports are determined based on the coordinated on-block (arrival) and off-block (departure) times. However, it is important to acknowledge that due to a variety of operational factors, the actual times of arrival and departure may deviate from the allocated slots.


To ensure the smooth functioning of slot allocation and optimize airport capacity, a continuous process known as Slot Monitoring is implemented. This process involves the ongoing comparison and reconciliation of actual operations with the slots assigned by the coordinator. The primary objectives of Slot Monitoring are as follows:


  • Ensuring Compliance: The monitoring process ensures that the actual operations align with the allocated slots, promoting consistency and orderliness in airport operations.
  • Use-It-or-Lose-It Rule: Slot Monitoring also verifies that the allocated slots are utilized in accordance with the Use-It-or-Lose-It rule. This rule mandates that airlines and operators must use their allocated slots adequately to maintain their historic rights.
  • Efficient Capacity Utilization: By closely monitoring slot usage, the aim is to optimize the utilization of limited airport capacity, maximizing efficiency and minimizing congestion.
  • Preventing Misuse: Slot Monitoring serves as a safeguard against any potential misuse of slots, ensuring fairness, transparency, and equal opportunities for all stakeholders.


Through diligent Slot Monitoring, coordinators work to maintain the integrity of the slot coordination process, enhance operational efficiency, and facilitate the smooth and effective management of airport slots.

The following actions are considered slot misuse when done intentionally or repeatedly:

  • Operating a flight without an allocated slot.
  • Operating a flight at a significantly different time than the allocated slot.
  • Operating a flight in a significantly different manner than the allocated slot without prior confirmation from the coordinator. This includes deviations in service type, aircraft sub-type, seats, origin/destination, and other relevant factors.
  • Holding or requesting slots that are not intended for actual operations.
  • Holding slots with the intention of denying capacity to other airlines or aircraft operators.


When assessing potential slot misuse, the coordinator takes into account the following factors:

  • Whether the deviation is a result of an obvious operational disruption, such as extreme weather conditions or strikes.
  • Whether the deviation falls within a reasonable tolerance, indicating normal operational variability.
  • Whether the deviation is part of a pattern involving repeated off-slot operations, departing from normal operational variability.


By considering these factors, the coordinator ensures a fair evaluation of potential slot misuse, taking into account genuine operational disruptions while addressing any intentional or repeated violations of slot allocation rules.

The coordinator conducts regular matching of actual operations with allocated slots by utilizing its aviation statistics analysis system, which provides a comprehensive list of flown operations. This matching process enables the identification of any discrepancies in the matched flight data, thereby helping to identify potential instances of slot misuse. This monitoring and analysis are performed consistently throughout the season.

Flights that are operated in accordance with their allocated slots, and were not initially assigned on an ad hoc basis, will be granted historic precedence. This means that these flights will receive priority treatment in subsequent equivalent seasons, ensuring a fair and equitable allocation of slots based on their adherence to the allocated schedule.

Upon identifying evidence indicating potential slot misuse, the coordinator will initiate written communication with the airline or aircraft operator involved. The purpose of this communication is to request an explanation for the identified discrepancy and to inquire about any proposed corrective measures the airline intends to implement.

If the airline fails to provide a satisfactory explanation or does not take appropriate corrective action within the provided timeframe, or if there is no response from the airline by the specified deadline, the coordinator will proceed to consider suitable enforcement actions.

This process ensures that airlines are given an opportunity to address and rectify any identified slot misuse. It promotes transparency, fairness, and compliance with slot coordination regulations.

When determining whether to initiate enforcement actions, the coordinator will take into account several factors related to slot misuse. These factors include:

  • Previous Warning: The coordinator will consider whether the slot misuse occurred after a warning was issued as part of the pre-operation analysis.
  • Occurrence and Pattern: The coordinator will assess if the misuse is a first-time occurrence or part of a recurring pattern.
  • Series of Slots or Ad Hoc Operation: The coordinator will examine whether the misuse is related to a series of slots or an ad hoc operation.
  • Potential Impact: The coordinator will evaluate the potential impact of the slot misuse on the airport, air traffic control(ATC) operations, or other airlines.


Enforcement actions for intentional or repeated slot misuse may involve the following measures:

  • Referral to MOLIT: The matter may be reported to the Ministry of Land, Infrastructure and Transport (MOLIT) for further investigation or actions.
  • Loss of Historic Precedence: In cases involving a series of slots, the airline may lose its historic precedence for those slots in the next equivalent season.
  • Lower Priority for Future Slot Requests: The airline may receive a lower priority for new slot requests in the next equivalent season.
  • Withdrawal of Slots: The series of slots involved in the misuse may be withdrawn for the remaining duration of the current season.


These enforcement actions aim to ensure compliance with slot allocation rules, maintain fairness among airlines, and safeguard the efficient operation of the airport.