Modification of the ATFM delay calculation (NM release 20.0)


Air Navigation Service Providers (ANSPs) noticed that the use of the Ready Message (REA) - whilst attempting to improve punctuality for aircraft – could result in artificial changes to the computed ATFM delay for individual flights and for the ANSP that has requested the regulation.

The ANSPs brought this to the attention of the Network Management Board (NMB). The ANSPs, together with the airspace users and the Network Manager reviewed the existing situation and developed a more accurate process which avoids artificial changes to the computed ATFM delay when a REA message is used.

The more accurate process was presented to the NMB and approved in March 2015 for implementation with NM software release 20.0 on April 04 2016.

The changes implemented with the release of NM software version 20.0 on 04 April 2016 reduce the overall level of computed ATFM delay. The changes are described in more detail in the relevant NM Release presentation .

Post Operations Performance Adjustment Process

The Post Ops Performance Adjustment Process allows operational stakeholders to notify national and European authorities of issues that relate to ATFM delay measurement, classification and assignment. It is a means of enhancing operational ATFM delay data used in the performance scheme (Regulation (EU) 390) – and thus a means of compliance with Article 21(3).

More information is available from the respective NM website .

Impact on this webpage

The ATFM delay related graphs shown on this web page and data in the download area take the change in methodology as of April 2016 into account.

In the ATFM delay file downloads, the computation method is indicated in the column “ATFM version”

ATFM version REA message adjustment Post ops adjustment
Version 1 No No
Version 2 Yes No
Version 3 Yes (as of 04 April 2016) Yes