Air navigation service provider (ANSP) Nav Canada will require that aircraft be equipped to transmit their position by automatic dependent surveillance-broadcast (ADS-B) Out by Feb. 23, 2023 when flying above 12,500 ft. and will phase in the requirement for lower airspace classes “no sooner than 2026.”

ADS-B Out capability has been required to operate in U.S. controlled airspace since January 2020. Canada’s mandate, which was originally set to begin in 2021, differs from the U.S. requirement in that operators must equip their aircraft with 1090 MHz Extended Squitter (1090ES) transponders and both top-and-bottom-mounted antennas to facilitate data reception by the Aireon space-based ADS-B system.

The FAA conducts aircraft surveillance using a network of ground-based ADS-B radio stations as well as radar and multilateration sensors, and allows operators to use either 1090ES transponders or 978 MHz UAT transceivers to broadcast position when flying below 18,000 ft. A 1090ES transponder is required above that level.

“ADS-B is a foundational building block for our future airspace and operations,” said Nav Canada President and CEO Raymond Bohn, who announced the mandate on Feb. 11. “The Canadian equipage mandate, when combined with Nav Canada’s space-based surveillance capabilities, will enhance safety and service.”

Nav Canada started applying ADS-B for surveillance using ground stations for reception in 2009 over the Hudson Bay, where ADS-B Out capability is required to receive surveillance-based separation services from air traffic control. The privatized ANSP is also the major shareholder in the Aireon joint venture, which in April 2019 formally launched its space-based ADS-B system using receivers mounted on Iridium Next satellites. 

Nav Canada now uses space-based ADS-B for properly equipped aircraft over the Hudson Bay, its sector of the North Atlantic Ocean and in domestic airspace above 29,000 ft. In December 2021, it started providing ADS-B service for equipped aircraft below 29,000 ft. in the Montreal Flight Information Region (FIR). Plans call for expanding the service to the Edmonton and Winnipeg FIRs later this year in advance of the mandate entering force early next year.

Antenna Diversity

The mandate was postponed from the earlier planned implementation to allow Nav Canada and regulator Transport Canada more time to develop the regulatory framework and an equipment certification process for its “antenna diversity” requirement to interact with the Aireon space-based system. Operators can meet the requirement by installing both top- and bottom-mounted transponder antennas or by using a single antenna that is capable of transmitting both toward satellites and the ground.

Complying with the mandate will be a challenge mainly for smaller, general aviation (GA) aircraft that may not be fitted with either dual antennas or 1090ES transponders. In background information on the mandate, Nav Canada explains that the first phase applies to Class B (12,500-to-18,000 ft.) and A (18,000-to-60,000 ft.) airspace where GA aircraft do not generally fly.

“Prior to establishing an ADS-B mandate in controlled airspace below 12,500 ft.—including but not limited to class C, D or E control zones, class E airways, Terminal and Transition areas—specific guidelines will be developed and coordinated to ensure that the concerns of affected operators are addressed and mitigated,” the ANSP says. “Such a mandate will be implemented no sooner than 2026. Nav Canada recognizes that there is a cost to adequately equip aircraft, and this is being considered in the timelines and airspace classification.”

The ANSP says it is also having discussions with vendors “who may wish to deploy” a Flight Information Services-Broadcast (FIS-B) data stream containing weather and aeronautical information—a service the FAA provides for free to aircraft equipped with 978 MHz UAT transceivers.