Supporting operations, monitoring activities and developing new technologies.

AWARENESS CAMPAIGN FOR PILOTS: Don’t use the datalink channel for voice communication! Click here for more info.

Datalink campaign


EUROCONTROL would like to raise awareness among pilots to keep VHF channels (136.500 -137.000 MHz) reserved for datalink free from voice communication to ensure most efficient communication between air traffic control (ATC) and pilots. Datalink is a key enabler to increase aviation safety and capacity as well as support automation, efficiency and scalability for airspace operations.

While monitoring flights over Europe, EUROCONTROL discovered that the dedicated radio frequencies supporting the air-ground datalink service (CPDLC) used for digital clearances have been misused for voice communication causing a failure of datalink exchange between air traffic control and aircraft. Pilots may have thought these channels are not in use because there is nothing audible, but the channels are effectively in use. On these occasions the provision of efficient air traffic services have been delayed causing unnecessary workload for pilots and controllers during these flights.

In addition, such difficulties undermine the trust in datalink and in future solutions involving this technology. As a means of passing instructions between air traffic controllers and pilots using text messages, datalink has the advantage of reducing the margin of error and misunderstandings in situations of poor voice connection, and liberating space on the congested VHF channels for critical voice communications. While datalink frequencies are selected automatically by the avionics, voice frequencies are dialled in manually, hence the need to raise awareness among airspace users to carefully check the VHF radio configuration.


Datalink refers to digital air/ground communications between aircraft and ground systems. The European datalink system is based on the Aeronautical Telecommunications Network (ATN) using interconnected routers and end systems, and VHF Digital Link Mode 2 (VDL Mode 2/VDL2), as the air/ground datalink technology.

VDL2, an ICAO standardized radio technology operating in the very high frequency (VHF) band, enables the air/ground communication exchanges with aircraft. In the future, other radio technologies are expected to be incorporated as part of the Future Communications Infrastructure (FCI) , such as:


Satellite communications datalink


L-band digital aeronautical communication system


Aeronautical mobile airport communications system datalink


Datalink enables applications such as Controller-pilot datalink communications (CPDLC). CPDLC allows flight crews and air traffic controllers to exchange non-urgent Air Traffic Control (ATC) information by data messages instead of voice radio. Text-based messages have the advantages to reduce the margin of error and misunderstandings in situations of poor voice connection, and they liberate space on the congested VHF channels for more urgent voice communications. Operators also use datalink to transmit Airline Operational Control (AOC) messages between flight crew and airline operational centres.


Datalink is the key enabler to increase aviation safety and capacity as well as support automation, efficiency and scalability for airspace operations. Datalink is paving the way towards the target SESAR concept: the introduction of 4D trajectory management and support for the coordinated air and ground integration of ATM.


Datalink services (DLS) are mandated in Europe with EC Regulation (EU 29/2009), referred to as the DLS Implementing Rule (DLS IR). The DLS IR, following various amendments of the initial regulation, is now since February 2020 in full force. The DLS IR requires the air navigation service providers (ANSPs) to offer four datalink services (DLIC, ACL, ACM and AMC ) and the airspace operators to be capable (i.e. to have equipped aircraft and trained crews) to operate these services over ATN VDL2 for all flights in the European airspace operating above FL285.

Datalink illustration

Our role

EUROCONTROL, together with the European Aviation Safety Agency (EASA) and SESAR Deployment Manager, aim to ensure an effective and harmonised datalink implementation in Europe. To this effect, EUROCONTROL has established the Datalink Performance Monitoring Group (DPMG) and together with EASA and SDM the Datalink Support Group (DSG) which bring together all relevant European and global stakeholders: Aeronautical Communication Service Providers, Aircraft Operators, Air Navigation Service Providers, National Regulators and manufacturing industry (avionics and OEMs)s. These groups support stakeholders to monitor their current datalink operations and solve technical issues affecting safety, capacity, performance and interoperability on a European level.

Overall, the EUROCONTROL Network Manager datalink activities cover the following three main areas of activities:

Performance monitoring

The Datalink Performance Monitoring Function (DPMF) is part of the European Commission Network Manager Functions Implementing Rule (NMFIR 2019/123) and aims to monitor the performance of datalink, supporting all stakeholders in the deployment and operation of datalink in Europe and to identify and report performance issues as required. NM has established the Datalink Performance Monitoring Group (DPMG), which oversees the performance monitoring  functions in the European data link service. Its purpose is to monitor the performance of the European data link system to allow stakeholders to understand how well the system is performing and to provide insight as to why the system is performing the way it is. The DPMG is intended to support many different stakeholder communities and, as such, provides performance data at different levels of detail and from different perspectives. The work of the DPMG is stakeholder-led with EUROCONTROL providing the secretariat and technical support’

The DPMF provides monthly, annual and ad-hoc (on request) performance reports together with a stakeholder dashboard that allow them to compare their performance against the European average. In order to complement ground monitoring data, monitoring flights are performed twice a year over the core of the European datalink airspace.  Forecast of the future VDL2 load, helping future frequency management, is provided in the annual report.

EUROCONTROL also coordinates the Logon List on behalf of some ANSPs and maintains a related database of aircraft and their associated data link avionics in operating in the European airspace. For more information, contact us.

Support datalink deployment and investigations

The aim of these activities is to steer and support the efficient datalink implementation in Europe and to undertake technical investigations of reported problems. The EUROCONTROL Network Manager (NM), jointly with EASA and SDM, have established the Datalink Support Group (DSG), which actively pursues the resolution of technical issues in the European datalink system. The group promotes discussion between affected stakeholders (aircraft operators, ACSPs, ANSPs and manufacturers), analyses technical and operational issues as required by the EC Regulation No 29/2009, and proposes technical and/or operational solutions to the relevant stakeholders.

EUROCONTROL provides the secretariat to the DSG, and facilitates technical support. Problem reporting, technical investigations, resolution agreement and deployment monitoring are performed by the Datalink Support Team (DST), composed by stakeholders and facilitated by EUROCONTROL NM, which reports to the DSG.

Datalink issue management tool

Reported issues are recorded and resolution process documented in the Datalink Issue Management tool. This process is intended for any kind of problem experienced in the implementation and usage of datalink services in Europe (e.g. operational usage of DLIC, ACM, ACL and AMC, ATN usage, accommodation of FANS 1/A aircraft, VDL2 usage, or any specific piece of technical equipment).

While DST focuses on technical problems, the Operational Focus Group (OFG), another DSG subgroup, addresses items with primarily an operational dimension and helps to progress the resolution of the operational problems and harmonise the datalink usage across Europe. Other ad-hoc DSG groups address specific issues such as the resolution of problems in accessing the datalink service of operators only doing ATC and developing guidelines on the best usage of AOC in order to optimise the loading of the VDL2 channels.

For further information on DSG and the EUROCONTROL support to datalink deployment activities please contact us.

Interoperability testing

The EUROCONTROL Datalink Test Facility (DTF) in the Experimental Centre is used to perform interoperability testing of datalink systems, reducing operational risks and overall costs for commercial products and systems used for operations. Through the DTF, we support the interoperability testing of ATN/CPDLC avionics, ANSP ground systems and CSP air/ground systems prior to their operational use:

We support avionics implementation for:

  • integration testing;
  • non-regression testing;
  • rehearsal for certification process;
  • verification of HMI and functioning of new equipped aircraft;
  • CPDLC familiarisation from equipped aircraft;
  • problem Investigation;

We support ANSP ground implementation for:

  • validation of Network Access;
  • integration testing;
  • non-regression testing;
  • problem investigation.
  • We may as well support ANSPs in their declaration of verification process.

We support CSP implementation for:

  • integration testing;
  • non-regression testing;

For further information on the EUROCONTROL interoperability testing activities and to make a request for datalink testing please use the form below.

EUROCONTROL Network Manager is also working with all ATM stakeholders (ANSPs, Airports and Airlines) as well as the Datalink Stakeholders to address the required evolution of the current VDL2 infrastructure and set up collaborative and efficient mechanisms to address problems and implement the agreed solutions.



Controller-pilot datalink communications ground automated tool

CPDLC mock-ups

Pilot’s and ATCO’s controller-pilot datalink communications mock-ups


Statistic analysis of datalink

Datalink issue management tool

Datalink application test tools

Datalink Dashboards

Other datalink activities

We provide support on the civil-military interoperability aspects. The DLS regulations lay down requirements on datalink services for the Single European Sky also for military users. Articles 3 and 8 of the Regulation 29/2009 contain provisions which affect State aircraft. The Regulation promotes the forward-fitting of transport-type State aircraft with the appropriate equipment where the military decide to equip aircraft with the civil datalink capability. Details on the applicability of the Regulation to State aircraft can be found in our CMAC CNS factsheet.


Explore our datalink tools, designed to help with monitoring and support,  in implementation activities, such as problem investigations, as well as helping with problem reporting and interoperability testing requests.



Datalink issue management tool


Statistic analysis of datalink