Minutes of en route ATFM delay per flight


Contact organisation EUROCONTROL: The European organisation for the safety of air navigation
Contact organisation unit Directorate European Civil-Military Aviation - Performance Review Unit (DECMA/PRU)
Contact name Performance Review Unit - EUROCONTROL
Contact mail address 96 Rue de la Fusée
1130 Brussels
Contact e-mail address [email protected]

Metadata update

Metadata last certified not applicable
Metadata last update 16 August 2021

Statistical presentation

Data description

The measure provides an indication of ATFM delays on the ground due to constraints en-route.

In accordance with EU legislation, Single European Sky Area States are required to adopt performance targets contributing adequately to and be consistent with the EU wide targets. The capacity KPI is the en route ATFM delay per flight.

In Europe, when traffic demand is anticipated to exceed the available capacity in en route centres or at airports, Air Traffic Control (ATC) units may request the local Flow Management Position (FMP) to instigate an Air Traffic Flow Management (ATFM) measure, or regulation. Aircraft expected to arrive during a period of congestion are given Air Traffic Flow Management delay at their departure airport, under the authority of the Network Manager, in order to regulate the flow of traffic into the constrained downstream en route sector or airport, thus ensuring safety. The resulting ATFM delays are calculated as the difference between the estimated take-off time calculated from the filed flight plan including updates and the calculated take-off time allocated by the central unit of ATFM. The reason for the regulation is indicated by the responsible Flow Management Position (FMP). The delay is attributed to the FIR containing the reference location of the most constraining capacity constraint.

En route ATFM delay has been in use as a commonly agreed proxy for en route capacity shortfalls since 1999. The calculation of ATFM delays is based on a well established and commonly accepted algorithm and is compliant with the KPI definition in the EU legislation.

Classification system

En route ATFM delay per flight is classified per:

It should be noted that the areas of responsibility of the individual ANSPs are not necessarily coincidental with the geographical boundaries of the State.

For the monitoring of National/FAB Performance targets, the FAB is considered as the aggregation of the individual FIRs belonging to the Member state within the FAB.

Sector coverage

The measures pertain to the Air Transport and Air Traffic Management Sector of the economy.

Statistical concepts and definitions

ATFM delay
ATFM delay is defined as the duration between the last Estimated Take-Off Time (ETOT) and the Calculated Take-Off Time (CTOT) allocated by the Network Manager. ATFM delay comprises both Airport ATFM delay] and En route ATFM delay. This indicator is solely concerned with En route ATFM delay.
The delay is truncated to minutes.
All the IFR flights which have filed a flight plan and have entered the area of responsibility of the relevant ANSP(s) are taken into account.
Each flight is only counted once, regardless of its trajectory.

Attribution of Delay

ATFM delay to which a flight is subjected is defined to have as cause the most penalizing ATFM regulation which affects it. Depending of the type and the entity responsible for the reference location protected by the ATFM regulation the ATFM delay is classified as either an airport or an en route ATFM delay and attributed to airport or en route facilities.

Each ATFM regulation also comprises a designator referring to the cause of delay which can be used in further analysis.

Statistical unit

The statistical unit is the State/ANSP to which the ATFM delays are attributed.

Statistical population

The statistical population comprises the States in the Single European Sky Area.

Reference area

The reference area is the Single European Sky Area.

Time coverage

2012 is the first year for which data is presented.

Base period

Not applicable.

Unit of Measure

The en route ATFM delay is measured in minutes per IFR flight.

Reference period

  • The first reference period (RP1) covers the calendar years 2012 to 2014 inclusive.
  • The second reference period (RP2) covers the calendar years 2015 to 2019 inclusive.
  • The third reference period (RP3) covers the calendar years 2020 to 2024 inclusive.

Unless decided otherwise, the following reference periods shall be of five calendar years.


Release policy

Release calendar

En route ATFM delay data is released 12 times per year, once per month.

Release calendar access

Not applicable.

User access

Information is disseminated to the general public via the SES Data Portal.

Frequency of dissemination

En route ATFM data is published monthly with the annual performance aggregate being available in January of the following year.

Dissemination format

Information is disseminated to the general public via the SES Data Portal.

Accessibility of documentation

Documentation on methodology

As per the pertaining regulations (see Institutional Mandate).
For technical questions not addressed in Statistical processing please contact: [email protected].
Additional definitions of the terms used in the frame of the this KPI are available in the Metadata page.

Quality documentation

There is no specific documentation on procedures applied for quality management and quality assessment.

Quality Management

Quality assurance

The data is provided by the Network Manager and as such it is their responsibility to perform any quality assurance activities.

Quality assessment

Data is validated by random quality checks, e.g. missing data for given a day, adherent data, etc. Any issues are reported to the Network manager who works with the EUROCONTROL Performance Review Unit to resolve them.


The information is published for performance monitoring purposes in accordance with the relevant EU legislation.


The data is collected for the entire Single European Sky Area.

Accuracy and reliability

Overall accuracy

The en route ATFM delay is the delay calculated by the Network Manager. This calculation is based on a well established methodology, which has been in place since 1999.

It is assumed that the data provided is accurate, given the caveats mentioned in sections Quality assurance and Quality assessment.

Sampling error

There is no sampling and therefore no sampling error.

Timeliness and punctuality


The full set of Minutes of en route ATFM delay per flight is published each month - in general between 14 and 16 days after the end of the month in question.


The internal databases are updated daily. The statistical processing is performed once per month.


Comparability — geographical

The data is collected centrally by the Network Manager and computed consistently throughout the entire Single European Sky Area which allows comparisons across different units.

Comparability over time

Comparisons over time are valid.


Coherence — cross domain

ATFM delay is calculated relative to the flight plan.

Although not fully cohered, the delay reported by aircraft operators to CODA under the corresponding IATA delay categories shows a high correlation with the ATFM delay calculated by the Network Manager. It should be noted that the delay reported by aircraft operators relates to airline schedules rather than flight plan.

Coherence — internal

Data is fully coherent from an internal perspective.

Cost and burden

Not available.

Data revision

The data revision policy has not yet been defined.

Statistical processing

Source data

Actual en route ATFM delay

Actual Number of IFR flights

Please note that, for operational purposes, the delays caused by READY to Depart (REA) messages and ATFM slot extensions were excluded from the ATFM delay computation with NM release 20 (4 April 2016) which reduces the overall amount of computed ATFM delay. More information on the adjusted ATFM delay computation as of NM release 20.0 from 4 April can be found here: NM release 20.0 - 4 April 2016 - FB750-Delay Calculation improvements.

Frequency of data collection

Data is collected for each individual flight in real time.

Data collection

Data is collected and compiled by the Network Manager.

Data validation

Data validation is the responsibility of the Network Manager.

Data compilation

The data can be aggregated at different levels.

Reference period EU wide Local
RP1 SES RP1 area Functional Airspace Block, Air Navigation Services Provider
RP2 SES RP2 area Functional Airspace Block, Country FIR
RP3 SES RP3 area Functional Airspace Block, Air Navigation Services Provider


Corrections may be made when issues are discovered as described in the Quality Assessment section of this document.

Post-operations performance adjustment

The post-operations performance adjustment process is a means of enhancing operational ATFM delay data used in the Single European Sky performance scheme. It allows operational stakeholders to notify national and European authorities of problems related to air traffic flow management (ATFM) delay measurement, classification and assignment. The main output of this process is a separate performance dataset, which will include the approved changes. Read more about the post-operations performance adjustment process.


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This data is published by the Performance Review Body (PRB) of the Single European Sky. Every effort has been made to ensure that the information and analysis contained on this website are as accurate and complete as possible. Despite these precautions, should you find any errors or inconsistencies we would be grateful if you could please bring them to the Performance Review Unit’s attention.

The information may be copied in whole or in part providing that the copyright notice and disclaimer are included. The information may not be modified without prior written permission from the PRB. The views expressed herein do not necessarily reflect the official views or policy of EUROCONTROL or of the European Commission, which make no warranty, either implied or express, for the information contained on this website, neither do they assume any legal liability or responsibility for the accuracy, completeness or usefulness of this information. The PRB reserves the right to change or amend the information provided at any time and without prior notice.