Attention:
All Canadian and foreign operators equipped with a radio altimeter and air traffic service
| File Classification No.: | Z 5000-35 |
|---|---|
| RDIMS No.: | 21440240 |
| Document No.: | CASA 2026-08 |
| Issue No.: | 02 |
| Effective Date: | 2026-06-18 |
Purpose:
The purpose of this Civil Aviation Safety Alert (CASA) is to communicate upcoming changes to the 5G spectrum environment in Canada following the voluntary extension of 5G mitigation measures described in CASA No. 2025-14. Major telecommunications service providers in Canada have reached an agreement to implement a set of voluntary 5G mitigations after June 30, 2026, in consultation with Transport Canada (TC), Innovation, Science and Economic Development Canada (ISED) and key aviation industry stakeholders.
This will ensure that on July 1, 2026, the spectrum environment in Canada will continue to protect tolerant Radio Altimeters (RadAlt) as defined in TC issued Airworthiness Directive (AD) CF-2024-14 (for fixed-wing aircraft) and CF-2024-15 (for rotorcraft) Footnote 1.
Background:
As stated in CASA No. 2025-14 and described in Appendix B, certain regulatory 5G spectrum mitigations were planned to sunset in January 2026, (i.e., reduced fundamental emissions power levels based on antenna uptilt above the horizon nationwide and exclusion/protection zones at 35 initially protected airports for the 3500 MHz band), but were extended voluntarily by Canadian telecommunications service Providers until the end of June 2026.
Since January 2026, TC, ISED, aviation and telecommunications stakeholders have collaborated to determine how to safely lift 5G mitigations measures.
Upcoming 5G environment:
In April 2026, in consultation with TC, ISED, and key aviation industry stakeholders, major telecommunications service providers in Canada have reached an agreement to implement voluntary 5G mitigations for the 3450-3900 MHz band after June 30, 2026. These include
- A commitment that outdoor base stations remain cross-polarized with equal power distribution between polarizations; and
- A limit of minus 42 dBm/MHz conducted power (sum of conducted power across all antenna connectors) for spurious emissions falling withing the 4200-4400 MHz frequency band.
The following additional voluntary 5G mitigations for the 3650-3900 MHz band:
- Outdoor base stations deployed at a height greater than 70 meters above ground level (AGL) in proximity to 245 airports be coordinated with Transport Canada and ISED at least 30 days before deployment; and
- An E.I.R.P. mask is implemented for all outdoor base stations operating between 3650-3900 MHz in Canada. This National EIRP mask is described in Appendix D.
Appendix B describes in detail the regulatory and voluntary changes to the 5G spectrum environment in Canada.
The telecommunications service providers have reached an agreement to implement the above voluntary 5G mitigations from 1 July 2026 until December 31, 2027. In January 2027 and July 2027, TC and ISED will check-in with the aviation industry and telecommunications licensees to ensure that the voluntary commitments can be lifted without any issues or determine if an extension of the voluntary commitments is required beyond January 1, 2028.
Ongoing recommended action:
- TC continues to urge all operators, including foreign operators, to retrofit their aircraft to meet RadAlt tolerance requirements described in ADs CF-2024-14 (for fixed-wing aircraft) and CF-2024-15 (for rotorcraft) by securing maintenance slots, parts, and supplemental type certificates (STCs) if necessary. Non tolerant configurations not yet addressed by TC or the Federal Aviation Administration (FAA) ADs, when operating in Canadian airspace, may be subject to more restrictive aviation limitations. Foreign aircraft with non tolerant configurations not yet addressed by TC or the Federal Aviation Administration (FAA) ADs should also abide by the more restrictive aviation limitations listed in the ADs when operating in Canadian airspace.
- In the event of an actual disturbance of radio altimeter, it is imperative that flight crew report the event to the Air Traffic Service as soon as possible, regardless of the location of the occurrence be it domestic or foreign airspace. Pilot in command and operator are to complete the ‘Radio Altimeter Disturbance/Interference Report’ in Appendix E: Radio Altimeter Disturbance/Interference Report. RadAlt Disturbance/interference Reports would assist TC in assessing 5G interference and are strictly non-punitive. Operators reporting RadAlt disturbance/interference will not be penalized where irregular flight operations are caused by a malfunctioning RadAlt. TC is thankful for the voluntary cooperation of all operators in this process.
- Transport Canada continues to engage its United States counterparts as well as its aviation stakeholders to assess existing aviation safety risks in all weather conditions, particularly for aircraft that are equipped with Radio Altimeters that are not 5G-tolerant and develop aviation-side mitigations to safeguard Canada’s aviation system while protecting the continuous flow of air traffic.
Contact office:
For more information concerning this issue, contact the AART Documentation Services AARTDocServices-ServicesdocAART@tc.gc.ca.
Jamie-Lee MacDermid
Executive Director, Standards branch
Civil Aviation
The Transport Canada Civil Aviation Safety Alert (CASA) is used to convey important safety information and contains recommended action items. The CASA strives to assist the aviation industry's efforts to provide a service with the highest possible degree of safety. The information contained herein is often critical and must be conveyed to the appropriate office in a timely manner. The CASA may be changed or amended should new information become available.
Appendix A: Criteria for Radio Altimeter Tolerance in Canada
In Canada, Radio Altimeter tolerance requirements are established in TCCA ADs CF-2024-14 (for fixed-wing aircraft) and CF-2024-15 (for rotorcraft).
These ADs also confirmed that aircraft meeting FAA AD 2023-10-02 RadAlt tolerance requirements (for fixed-wing aircraft) and FAA AD 2023-11-07 (for rotorcraft) are considered RadAlt tolerant in Canada.
Appendix B: List of effective 5G mitigations in Canada
In Canada, prior to January 1, 2026 and extended by voluntary agreement until June 30, 2026:
| Frequency Band Footnote 2 | Where | Airport EIRP elevation mask Footnote 3 | National Tilt restriction Footnote 4 | Height/Power Combination limits Footnote 5 | Exclusion zone Footnote 6 | Max possible Power Footnote 7 | Max possible Spurious (TRP or conducted) Footnote 8 |
|---|---|---|---|---|---|---|---|
| 5G 3500 MHz (3450 to 3650) | At protected airports | Yes | N/A, other is more restrictive | Yes - Loosely "Based" on FAA Group 3A curve. Footnote 9 | Yes | 61 dBm/MHz EIRP | -30 dBm/MHz |
| At Non-protected Airports | No | Yes | No, only tower obstruction limits afforded by OCS. Footnote 10 | No | 61 dBm/MHz EIRP | -30 dBm/MHz | |
| 5G 3800 MHz (3650 to 3900) | At protected airports | Yes | N/A, other is more restrictive | Yes - "Based" on FAA Group 3B curve. | Yes | 61 dBm/MHz EIRP | -30 dBm/MHz |
| At Non-protected Airports | No | Yes | No, only tower obstruction limits afforded by OCS. | No | 61 dBm/MHz EIRP | -30 dBm/MHz |
In Canada, on July 1, 2026 by voluntary agreement:
(changes from CASA 2025-14 marked in bold and with a *)
| Frequency Band | Where | Airport EIRP elevation mask | National Tilt restriction Footnote 11 | Height/Power Combination limits | Exclusion zone | Max possible Power | Max possible Spurious |
|---|---|---|---|---|---|---|---|
| 5G 3500 MHz (3450 to 3650) | At protected airports – None remaining | No* | No* | No* | No* | 61 dBm/MHz EIRP | -42 dBm/MHz* |
| At Non-protected Airports | No | No* | No | No | 61 dBm/MHz EIRP | -42 dBm/MHz* | |
| 5G 3800 MHz (3650 to 3900) | At protected airports | Yes | N/A, other is more restrictive | Coordination with TC for towers taller than 70 m at 35 protected airports. | No | 61 dBm/MHz EIRP | -42 dBm/MHz* |
| At Non-protected Airports | No | Yes, as described in Appendix D*. | Coordination with TC for towers taller than 70 m at 210 non-protected airports. | No | 61 dBm/MHz EIRP | -42 dBm/MHz* |
Appendix C: List of protected runways
Table 1 identifies the runways which are voluntarily protected for the 3500 MHz band and 3800 MHz band until June 30, 2026, and which will remain protected by agreement for the 3800 MHz band until December 31, 2027.
Table 1: 5G Protected Runways
| Airport Name | Protected Runways | |
|---|---|---|
|
1 |
Abbotsford International Airport/Aéroport International d'Abbotsford | RWY-07/25 |
|
2 |
Calgary International Airport/Aéroport International de Calgary | RWY-08/26 |
| Calgary International Airport/Aéroport International de Calgary | RWY-11/29 | |
| Calgary International Airport/Aéroport International de Calgary | RWY-17L/35R | |
| Calgary International Airport/Aéroport International de Calgary | RWY-17R/35L | |
|
3 |
Charlottetown International Airport/Aéroport International de Charlottetown | RWY-03/21 |
| Charlottetown International Airport/Aéroport International de Charlottetown | RWY-10/28 | |
|
4 |
Churchill Airport/Aéroport de Churchill | RWY-15/33 |
|
5 |
Comox Valley Airport/Aéroport de Comox Valley | RWY-12/30 |
| Comox Valley Airport/Aéroport de Comox Valley | RWY-18/36 | |
|
6 |
Deer Lake Regional Airport/Aéroport Régional de Deer Lake | RWY-07/25 |
|
7 |
Edmonton International Airport/Aéroport International d'Edmonton | RWY-02/20 |
| Edmonton International Airport/Aéroport International d'Edmonton | RWY-12/30 | |
|
8 |
Erik Nielsen Whitehorse International Airport/Aéroport International Erik Nielsen de Whitehorse | RWY-14R/32L |
|
9 |
Fort McMurray International Airport/Aéroport International de Fort McMurray | RWY-08/26 |
|
10 |
Fredericton International Airport/Aéroport International de Fredericton | RWY-09/27 |
| Fredericton International Airport/Aéroport International de Fredericton | RWY-15/33 | |
|
11 |
Gander International Airport/Aéroport International de Gander | RWY-03/21 |
| Gander International Airport/Aéroport International de Gander | RWY-13/31 | |
|
12 |
Goose Bay Airport/Aéroport de Goose Bay | RWY-08/26 |
| Goose Bay Airport/Aéroport de Goose Bay | RWY-15/33 | |
|
13 |
Greater Moncton Roméo LeBlanc International Airport /Aéroport International Roméo LeBlanc du Grand Moncton | RWY-06/24 |
| Greater Moncton Roméo LeBlanc International Airport /Aéroport International Roméo LeBlanc du Grand Moncton | RWY-11/29 | |
|
14 |
Halifax Stanfield International Airport/Aéroport International de Halifax | RWY-05/23 |
| Halifax Stanfield International Airport/Aéroport International de Halifax | RWY-14/32 | |
|
15 |
Iqaluit Airport/Aéroport d'Iqaluit | RWY-16/34 |
|
16 |
J.A. Douglas McCurdy Sydney Airport/Aéroport de Sydney J.A. Douglas McCurdy | RWY-06/24 |
| J.A. Douglas McCurdy Sydney Airport/Aéroport de Sydney J.A. Douglas McCurdy | RWY-18/36 | |
|
17 |
John C. Munro Hamilton International Airport /Aéroport International John C. Munro d'Hamilton | RWY-06/24 |
| John C. Munro Hamilton International Airport /Aéroport International John C. Munro d'Hamilton | RWY-12/30 | |
|
18 |
Kelowna International Airport/Aéroport International de Kelowna | RWY-16/34 |
|
19 |
London International Airport/Aéroport International de London | RWY-09/27 |
| London International Airport/Aéroport International de London | RWY-15/33 | |
|
20 |
Mirabel International Airport/Aéroport Internationale de Mirabel | RWY-06/24 |
| Mirabel International Airport/Aéroport Internationale de Mirabel | RWY-11/29 | |
|
21 |
Montréal-Pierre Elliott Trudeau International Airport/Aéroport International Pierre Elliott Trudeau de Montréal | RWY-06L/24R |
| Montréal-Pierre Elliott Trudeau International Airport/Aéroport International Pierre Elliott Trudeau de Montréal | RWY-06R/24L | |
| Montréal-Pierre Elliott Trudeau International Airport/Aéroport International Pierre Elliott Trudeau de Montréal | RWY-10/28 | |
|
22 |
North Bay Jack Garland Airport/Aéroport North Bay Jack Garland | RWY-08/26 |
|
23 |
Ottawa International Airport/Aéroport International d'Ottawa | RWY-07/25 |
| Ottawa International Airport/Aéroport International d'Ottawa | RWY-14/32 | |
|
24 |
Prince George Airport/Aéroport International de Prince George | RWY-06/24 |
| Prince George Airport/Aéroport International de Prince George | RWY-15/33 | |
|
25 |
Québec City Jean Lesage International Airport/Aéroport International Jean-Lesage de Québec | RWY-06/24 |
| Québec City Jean Lesage International Airport/Aéroport International Jean-Lesage de Québec | RWY-11/29 | |
|
26 |
Regina International Airport/Aéroport International de Regina | RWY-08/26 |
| Regina International Airport/Aéroport International de Regina | RWY-13/31 | |
|
27 |
Saskatoon John G. Diefenbaker International Airport/Aéroport International John G. Diefenbaker de Saskatoon | RWY-09/27 |
| Saskatoon John G. Diefenbaker International Airport/Aéroport International John G. Diefenbaker de Saskatoon | RWY-15/33 | |
|
28 |
St. John’s International Airport/Aéroport International de St. John's | RWY-02/20 |
| St. John’s International Airport/Aéroport International de St. John's | RWY-11/29 | |
| St. John’s International Airport/Aéroport International de St. John's | RWY-16/34 | |
|
29 |
Stephenville Dymond International Airport/Aéroport International Stephenville Dymond | RWY-09/27 |
|
30 |
Thunder Bay International Airport/Aéroport International de Thunder Bay | RWY-07/25 |
| Thunder Bay International Airport/Aéroport International de Thunder Bay | RWY-12/30 | |
|
31 |
Toronto Pearson International Airport/Aéroport International Pearson Toronto | RWY-05/23 |
| Toronto Pearson International Airport/Aéroport International Pearson Toronto | RWY-06L/24R | |
| Toronto Pearson International Airport/Aéroport International Pearson Toronto | RWY-06R/24L | |
| Toronto Pearson International Airport/Aéroport International Pearson Toronto | RWY-15L/33R | |
| Toronto Pearson International Airport/Aéroport International Pearson Toronto | RWY-15R/33L | |
|
32 |
Vancouver International Airport/Aéroport International de Vancouver | RWY-08L/26R |
| Vancouver International Airport/Aéroport International de Vancouver | RWY-08R/26L | |
| Vancouver International Airport/Aéroport International de Vancouver | RWY-13/31 | |
|
33 |
Victoria International Airport/Aéroport International de Victoria | RWY-03/21 |
| Victoria International Airport/Aéroport International de Victoria | RWY-09/27 | |
| Victoria International Airport/Aéroport International de Victoria | RWY-14/32 | |
|
34 |
Winnipeg James Armstrong Richardson International Airport/Aéroport International James Armstrong Richardson de Winnipeg | RWY-13/31 |
| Winnipeg James Armstrong Richardson International Airport/Aéroport International James Armstrong Richardson de Winnipeg | RWY-18/36 | |
|
35 |
Yellowknife Airport/Aéroport de Yellowknife | RWY-10/28 |
| Yellowknife Airport/Aéroport de Yellowknife | RWY-16/34 |
Appendix D: National EIRP Mask (3650-3900 MHz) applicable outside of 35 designated airports
- An effective isotropically radiated power (EIRP) mask is implemented by agreement for all outdoor base stations operating in the 3650-3900 MHz band in Canada per table 1.
Table 1
| Combined antenna uptilt angle (relative to the horizon) | Maximum EIRP | |
|---|---|---|
| Less than or equal to 7 degrees above the horizon | 61 dBm/MHz | |
| Greater than 7 degrees to 10 degrees | 59.5 dBm/MHz | |
| Greater than 10 degrees to 13 degrees | 58 dBm/MHz | |
| Greater than 13 degrees to 16 degrees | 56.7 dBm/MHz | |
| Greater than 16 degrees 19 degrees | 55.8 dBm/MHz | |
| Greater than 19 degrees to 22 degrees | 55 dBm/MHz | |
| Greater than 22 degrees to 25 degrees | 54.3 dBm/MHz | |
Note 1: The antenna uptilt angle is calculated as the sum of the digital and mechanical tilt angles (relative to the horizon) for each fixed and base station antenna.
Note 2: Table 1 does not override the EIRP elevation mask for outdoor fixed and base stations deployed within the protection zones set out in Figure E.3 of SRSP-520 — Technical Requirements for Fixed and/or Mobile Systems, Including Flexible Use Broadband Systems, in the Band 3450-3900 MHz.
Appendix E: Radio Altimeter Disturbance/Interference Report
Available online:
Radio Altimeter Disturbance/Interference Report
