At EUROCONTROL's Maastricht Upper Area Control Centre (MUAC), we have been operating controller-pilot datalink communications (CPDLC) since 2003 to help mitigate the shortcomings of traditional voice communication.
CPDLC - an air/ground datalink application - offers the benefit of an additional, independent and secure channel, which reduces the strain on busy VHF sector frequencies, transmitting clear messages with no risk of misunderstandings. Use of the system increases capacity and safety; it improves the day-to-day efficiency of communications between controllers and pilots.
Currently, more than 50% of the traffic crossing the MUAC airspace receives some CPDLC clearances. We use it as a secondary communications medium, complementing VHF voice communications, which remains the primary means for tactical communication.
Additionally, since 2022, MUAC also supports ADS-C connections. ADS-C enables aircraft to automatically log on and downlink key aircraft intent flight management system information (e.g. the extended projected profile) to the MUAC system, which can be displayed on controllers’ screens.
As of February 2020, with some exemptions, CPDLC is required to operate above FL285 in Europe. In MUAC airspace, as indicated in AIP, every aircraft included in a log-on list is expected to log-on if technically capable.