In order to achieve interoperability between air traffic service units, there was a need to define the message transfer protocol to support On-Line Data Interchange (OLDI) using the internet protocol (IP).

The use of X.25 data communication networks to support ground-ground ATS data exchanges is becoming increasingly costly and has a limited lifespan. As a consequence, it was necessary to adapt the former EUROCONTROL Standard for Flight Data Exchange Interface Control Document from X.25 to TCP/IP.

This migration led to the development of the Single European Sky (SES) implementing rule and the EUROCONTROL Specification on Flight Message Transfer Protocol (FMTP),  which is recognised as a community specification supporting the Implementing Rule. This EUROCONTROL specification defines the interoperability and performance requirements for implementations of the FMTP.

OLDI over FMTP status of implementation is currently tracked by the use of the FMTP database under the governance of the OLDI-FMTP Implementation Support Group.


  • annual reports to ICAO EUR/NAT Regional Office;
  • reports to PENS PSSG;
  • FMTP database regular updates.


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