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NAV CANADA Improves Communications Between Pilots and Controllers

9 July 2014

Canadian airspace has undergone safety and efficiency enhancements with the completion of the national implementation of Controller Pilot Data Link Communications (CPDLC). CPDLC enables controllers in Area Control Centres (ACC) and pilots in suitably equipped aircraft flying above 29,000 feet to communicate via data link or text-based messages instead of voice. 

CPDLC delivers many safety and efficiency improvements over spoken communications broadcast over VHF or HF radio. Text messages provide greater clarity so the risk of communications errors is significantly decreased. 

“Miscommunication is a common air safety issue, but there is much less chance of error when both the flight crew and the controller have the ability to communicate using standardized text messaging,” said Rudy Kellar, Executive Vice President, Service Delivery. 

“CPDLC also improves efficiency,” noted Kellar. “Radio frequency congestion is relieved as voice communications are reduced. With data link there is no need to read-back and hear-back instructions, which often need to be repeated several times due to poor radio reception or voice quality due to static interference and poor reception.” 

Text messages also facilitate air traffic control communications with pilots whose first language is not English, a common occurrence as many intercontinental flights transit Canadian skies. 

CPDLC has a series of standardized text messages covering most routine communications. At air traffic control centres they are displayed on a drop-down menu enabling fast and efficient selection and transmission. (See photo). 

For example, CPDLC messages from flight crews could include a request to change altitude or speed. A typical message from controllers could be a route clearance or frequency assignment. Controllers also have quick response buttons for messages such as “Roger, Standby, Negative, or Unable.”. 

NAV CANADA first deployed CPDLC in December 2011 at the Montreal ACC where controllers manage air traffic over Quebec, along with parts of Nunavut and Eastern Ontario. The national rollout was completed in April 2014 when the Toronto ACC began employing the text-based communications system. 

“The NAV CANADA rollout of CPDLC represents one of the first and certainly the largest domestic implementation in the world to date,” noted Kellar. Data link communication had already been in use by NAV CANADA controllers working in the oceanic sector in Gander for more than a decade. 

The number of monthly CPDLC contacts in domestic airspace has seen more than a ten-fold increase from just over 7,000 messages in September 2012 to 76,000 in May 2014. 

NAV CANADA is the country’s private sector civil air navigation services provider. With operations from coast to coast to coast, NAV CANADA provides air traffic control, flight information, weather briefings, aeronautical information services, airport advisory services and electronic aids to navigation. 

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