CPDLC: freeing up the radio waves

In areas with high densities of air traffic, the use of text messages between pilots and air traffic controllers is gaining ground. They complement voice messages and facilitate air traffic control as well as making it safer. Thanks to its expertise, the EUROCONTROL Experimental Centre (EEC) has played a major role in the development of Controller-Pilot Data Link communications (CPDLC) technology since its inception in the 1990s.

The growing density of air traffic raises numerous challenges. In certain very busy flight areas such as central European airspace, radio communications between pilots and air traffic controllers are reaching saturation point. According to Paul Conroy, an operations expert at EUROCONTROL, “controllers are reaching their limits in relation to the amount of time/work dedicated to voice exchanges.” In addition, the quality of voice communications is not always satisfactory.


EUROCONTROL Experimental Centre – a vital player

Against this background, text messages have emerged to complement voice communications. Controller-pilot data link communications (CPDLC) free up the radio waves and allow a better sharing and spread of workload between controllers. They have also paved the way for the automation of routine tasks and hence an increase in air traffic management capacity. Another advantage is that a text message is always intelligible (never garbled), which increases safety.

As a mandatory prerequisite for its implementation, data link had to be evaluated and validated by a series of simulation exercises and studies in very-high- density traffic conditions. According to Robin Deransy, an expert analyst in the field at the time, “the EUROCONTROL Experimental Centre, with its real-time simulator, played a major role in the validation of this operational concept.” Since 1995, numerous controllers and pilots have been exposed to CPDLC and to its possibilities thanks to their participation in simulations and validation activities at the EEC. “Human factors were at the core of these test sessions and we resolved numerous problems: we designed and tested new pilot-controller procedures and human-machine interfaces adapted to CPDLC.


Future development up to 2020

The impact of this work is significant. The extensive data set collected through these validations have informed and influenced the drafting of a European regulation concerning the mandatory introduction of CPDLC in airspace with a high density of traffic between now and 2020. In Robin Deransy’s opinion, “CPDLC is well on track, numerous national control centres have already started to adopt it.