CPDLC Improves Safety in Canadian Airspace

by the Safety Planning, Performance and Promotion Division, NAV CANADA

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Controller-pilot data link communications (CPDLC) is now in place in Canadian Domestic Airspace (CDA) above FL 290. The national rollout of CPDLC began with the Montréal flight information region (FIR) in December 2011, and by February 2013, it had been deployed in six out of the seven FIRs, representing over 90 percent of Canada’s 15 million square kilometres of domestic airspace.

At the time of writing, the final piece of the puzzle was scheduled to be put in place later this year, when high level air traffic controllers at the Toronto area control centre (ACC) start using data link to communicate with pilots flying in the Toronto FIR—the busiest of the seven managed by NAV CANADA. With that final piece, Canada will become the first—and to date, only—country in the world to have CPDLC capability in the entirety of its domestic airspace.

CPDLC enables controllers in ACCs and pilots in cockpits to communicate via data link or text-based messages instead of voice. Text-based messages initiated by either the pilot or controller can be related to altitude, speed and route clearances; change requests; frequency assignments; or any related air traffic service information.

Communicating by text message has multiple advantages over voice, but it is the improvement to safety that is the focus of this article. With data link there is no need to read back and hear back instructions, which in some cases need to be repeated several times because of poor radio reception or voice quality due to interference.

Miscommunication can be a serious problem, but there is much less chance of pilot-controller communication errors when both the pilot and the controller have the ability to read, or even print, their messages. This is especially advantageous for ATC communication with pilots whose first language is not English, a frequent occurrence as many intercontinental flights transit Canadian skies.

NAV CANADA has already seen a significant drop in communication errors where CPDLC is used. This applies not only to read-back hear-back errors, but also to miscommunications that may arise where aircraft have similar sounding call signs.

The fact that pilots and controllers have a direct line of communication with each other is also a factor in reducing communication errors, as clearances are going to the right aircraft. There is no call sign confusion between Air Transat 115 and Air Canada 115, eliminating the chance of an aircraft getting the wrong clearance. It’s like moving from an analogue “party line” to direct digital communication.

Another safety benefit is in Canadian Northern Domestic Airspace (NDA), where most of the remote VHF radio frequencies don’t offer coverage redundancy in the event of a failure. CPDLC covers for frequency outages or maintenance, allowing controllers and pilots to stay in contact. 

Furthermore, CPDLC eliminates a lot of noisy chatter in the operations room at the ACC and reduces the sound of constant radio communications in the cockpit. And a quieter workplace improves concentration.

How does CPDLC work?

CPDLC employs a series of standardized text messages for most routine communications. These include over 200 “uplink messages” (from ATC to the cockpit) and more than 100 “downlink messages” (from the flight crew to controllers). Pilots and controllers also have the option of sending free-text messages.

For the most part, CPDLC works with the click of a mouse. Controllers have drop-down menus on their screens with the standard messages. Menus are divided into different categories to make the appropriate message easier to find. Each ACC can modify their drop-down menus and choose which messages are contained in each message group.

For instance, the Maintain (Alt), Climb to and Maintain (Alt), Descend to and Maintain (Alt), and At (POS) Climb to and Maintain (Alt) would likely go under the Altitude drop-down menu. Other common drop-down menus are Radio, Route, Speed, and Free text. There are also quick-response buttons for Unable, Roger, Negative, Standby and Deferred.

For downlink messages that require a response, the controller just has to click on that message and the appropriate drop-down menu, and the response is highlighted in green (as opposed to white), making the messages easier to find.

Usage and equipage

The number of monthly CPDLC contacts in domestic airspace has almost tripled in the 14-month period from November 2012 to December 2013: from just under 18 000 to nearly 53 000.

Those numbers are expected to continue to rise as the CPDLC equipage rate increases.

The percentage of CPDLC-equipped flights in Canada’s domestic high level airspace varies according to geographical location, from 27 percent in the central Canadian FIRs, to 79 percent near the country’s east coast.

In addition to the many safety enhancements, CPDLC adds an important efficiency benefit. As the need for voice communications decreases, the problem of radio frequency congestion becomes less of an issue. CPDLC also has a multiplier effect on alleviating frequency congestion when you calculate the number of flights using CPDLC. If one data link message can eliminate even 30 seconds of airtime, that can translate to 15 or more hours per day of voice communications taken off the airwaves.

And finally, for those of you who are wondering about the safety of pilots “texting while flying”, it is always the pilot monitoring (PM) who sends and receives the messages.

A Good Flight Plan May Be Your Saving Grace

by Captain Jean Houde, Aeronautical Coordinator, Joint Rescue Coordination Centre Trenton

Our last contribution to this newsletter covered the close relationship between your ELT and the SAR system, more specifically the abundance of false alarms mainly due to beacon mishandling.

To reduce the rate of false ELT alarms, our recommendation was for all aircrew to dial 121.5 MHz on their radio prior to shutdown, notify ATC as soon as they notice an inadvertent activation and very seriously consider purchasing a 406 MHz beacon if they have not already done so. Strangely enough, we have noticed a slight reduction in such incidents over the last year. Is the message getting through?

In this issue, let’s focus on the number two cause of SAR system activation: the flight plan. The flight plan is sometimes filled out in haste and with little thought as to how crucial it may become a few hours later. But aviators should realize that it circulates deep within NAV CANADA after it is submitted.

Once a VFR or IFR flight plan is activated, it remains open until you close it through an ATC agency at your arrival aerodrome. If a flight plan is not closed within 60 min, it is categorized as an overdue aircraft situation which activates the SAR system. When that happens, many people and agencies are pulled into the picture including ATC, the Joint Rescue Coordination Centre (JRCC), local police and airport operators.

The JRCC aeronautical coordinator is notified the moment an aircraft is deemed overdue and creates a new SAR case file, which entails initial search planning and mission coordination.

Preliminary investigation work includes ramp checks at the departure and arrival airports, often conducted by local police in the middle of the night. Emergency contacts are notified, the flight plan is analyzed, the route is verified, possible alternates are considered, weather throughout the proposed flight ascertained, a communication search is conducted and so on.

If the situation cannot be resolved quickly, SAR resources are tasked to commence the search.

When you complete your flight plan, it is vital that the route you file is accurate. Deviations from your filed plan are made at your own peril because, should you run into trouble, your flight plan indicates where we begin our search.

If you must deviate from your flight path, report to ATC directly or via relay through any passing aircraft above you. The crew of a commercial airliner at FL410 will hear your transmission up to 250 NM away because they monitor 121.5 MHz. Providing regular reports to ATC along your route will help us to determine how far you have progressed along your track. This information will ultimately help us better focus SAR assets and increase your chances of being found sooner.

Unlike the old days of watch-map-ground, most pilots rely on GPS to take them safely to destination so we tend to find most missing aircraft in close proximity to the filed track.

Always use Zulu time instead of local time to mark your departure. Pilots often use local time which can cause considerable confusion. Be precise in calculating your endurance as it helps us determine how far you could have flown and ultimately determines the size of the search area.

Do not list yourself as the emergency contact if you are the one flying the aircraft. Ensure that your emergency contacts can be reached and have information regarding your whereabouts and/or your aircraft.  

Once safely arrived at destination, remember that no job is finished until the paperwork is done. Make sure your flight plan is closed and check your ELT before shutdown. Tie a string on your thumb, if you have to, as a reminder before you leave the hangar and head home.

Even though it is not mandatory to file a flight plan when you fly within 25 NM of an aerodrome, let a responsible person know where you are going and have them call the JRCC or any ATC agency should they feel uneasy regarding your whereabouts. A 25-NM radius around an aerodrome is a larger search area than you think. In the absence of a flight plan with a clear proposed route, we have to search in ALL directions from the aerodrome and as far as your endurance can possibly take you. Imagine the size of the search!

Prepare for the elements

No one expects to spend one or several nights in the wilderness after taking off. But it happens, so you should be prepared. Dress for the occasion and in accordance with the outside weather in the region you are flying; bring survival gear, warm clothing, signaling equipment, matches, non-perishable food, water, etc. Since everyone carries a cell phone these days, carry yours with a full battery and leave it on throughout the flight. You would be amazed how many search areas were significantly reduced simply through cell phone pinging.

Better yet, because cell phones can be so helpful in resolving cases, bring a spare charged battery with you. Stay with the aircraft unless it puts you in danger; too many people walk away and this makes it even more difficult to find them. If your radio still works, make regular broadcasts on 121.5 MHz. If you can, start a fire and keep it going during the night. A fire stands out for many kilometres when seen from the air.

If you are in distress, ensure your ELT is activated—keep it activated until you are safely rescued. Leaving your beacon on even after you’ve been spotted by air is one more way you can help us help you.

All this to say: please be diligent in completing your flight plan, provide us with a means to contact a responsible person who can give us answers, stick to your filed route, expect the unexpected and call ATC after you land. The SAR service is here for you, but we need your help to find you in the most expeditious way. Safe flying!

Consolidation of Civil Aviation Online Applications and Services Under New Web Portal

Please note that external Web site access to the following Civil Aviation applications and systems can now be found at a single portal:

  • Approved Aircraft Simulators and Flight Training Devices (AASFTD)
  • Approved/Accepted Organizations (AO)
  • Authorized Person—Flight Crew Licensing (AP FCL)
  • Delegates Information System
    • Airworthiness Engineering Organization (AEO)
    • Approved Check Pilot (ACP)
    • Design Approval Organization (DAO) [This includes the authorized person(s) within the DAO.]
    • Design Approval Representative (DAR)
  • Flight Training
  • Minister's Delegate—Maintenance (MDM)
  • Operator List Search (OLS)

This change was necessary to ensure that Civil Aviation conforms fully to the Web Content Accessibility Guidelines (WCAG) and allowed for the decommissioning of six external Web portals. As part of the move towards a consistent layout for Government of Canada Web sites, stakeholders are able to find search utilities more easily via the new Web portal.

This new external Web portal was launched in May 2014. Anyone accessing the old Web portals will be redirected to the new site with a recommendation to change their bookmarks to the new Web portal address. Please note that redirection to this new site will only be in place for six months.

The new Web portal address is

2014 Transport Canada Aviation Safety Award


Left to right: Gilles Lapierre, President, Aviateurs et pilotes de brousse du Québec; Martin Eley, Director General of Civil Aviation, Transport Canada; Jean-Pascal Légaré, Regional representative, Québec region, Transport Canada; Bernard Gervais, Vice-President, Member Services, Aviateurs et pilotes de brousse du Québec; and The Honourable Lisa Raitt, Minister of Transport.

The Transport Canada Aviation Safety Award acknowledges the recipient’s sustained commitment and exceptional dedication to Canadian aviation safety over an extended period of time. For 2014, the award was presented to the Aviateurs et pilotes de brousse du Québec (APBQ) for their outstanding contribution to aviation safety.

The not-for-profit organization’s mission is to bring together and represent Quebec aviators in order to promote recreational aviation and bush flying; protect the right to fly; promote flight safety and accessibility; facilitate discussion among members; and provide access to assistance, training and information resources.

A passion for aviation and bush sports unites APBQ’s members, who come from diverse backgrounds. Founded in Montréal in 1979 as the Association des pilotes de brousse du Québec, the APBQ now has nearly 1 800 members, primarily in Quebec, but also in other parts of Canada and the world.  While it was originally an organization of bush pilots, today the majority of APBQ members are pilots of all types, with qualifications ranging from recreational permits to airline pilot licences.

Bush pilots were vital to the discovery and early development of Canada’s natural resources. Canada would not be the strong and vibrant country it is today without those aviation pioneers, or without John Alexander Douglas McCurdy whose first flight we celebrate on National Aviation Day, February 23. In the same way, those represented by the APBQ are intrinsic to Canada’s internationally recognized aviation safety record.

The APBQ continues to act as a leader and role model in innovation, training and advancement, striving towards greater aviation safety in Canada and around the world.

Transport Canada encourages you to nominate an individual or group who deserves recognition for next year’s Aviation Safety Award. For more information, please visit

Worth Watching—Again!

AOPA’s No Greater Burden: Surviving an Aircraft Accident

The story of Russ Jeter and his son Jacob

Produced by the Air Safety Institute division of the Aircraft Owners and Pilots Association (AOPA) Foundation, this powerful video brings home a very important message for all of us. Click on the linked title above to view. It is time well spent!

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