Controller–pilot datalink communications (CPDLC) is a method by which air traffic controllers can communicate with pilots over a datalink system in place of voice communication by data messages. The standard method of communication between an air traffic controller and a pilot is voice radio, using either VHF bands for line-of-sight communication or HF bands for long-distance communication.

Datalink Services Central Reporting Office (DLS-CRO) provides support to stakeholders in monitoring datalink operations and in resolving issues affecting safety, capacity, performance and interoperability at European level.

The functions of the DLS-CRO can be grouped under the following headings:

  • problem investigation - DLS-CRO provides a tool for problem reporting and will investigate any problem reports that are assigned to it, in collaboration with the required experts,
  • performance monitoring - DLS-CRO monitors the performance of the overall system and publishes a number of performance statistics, and
  • knowledge management - DLS-CRO aims to provide a central repository of knowledge regarding the introduction and operation on the datalink services in Europe.


  • Monthly operational CPDLC statistics;
  • Reports of overall End to End Performance;
  • Problem reports, investigation & resolution;
  • End to end system test capability;
  • Reference & Guidance Documents repository;
  • Support (technical, testing, safety and operational).


Access conditions

The service is restricted to specific stakeholder groups.