FAA Issues New 5G Operating Limits for Aircraft Flying to Canada

‍WASHINGTON — The Federal Aviation Administration (FAA) has issued new airworthiness directives requiring operating limits for aircraft not equipped with radio-altimeter systems proven tolerant of Canada’s revised 5G Lower C-band environment.

The directives take effect on July 1, the same day Canada is set to remove airport exclusion and protection zones that had limited the risk of 5G interference with aircraft radio altimeters.

The FAA said the change will create a more severe interference environment for aircraft whose equipment has not demonstrated the required tolerance. The agency’s broad directive applies to transport and commuter-category aircraft equipped with radio altimeters, including aircraft built by Airbus, Boeing, Embraer, Bombardier, ATR, De Havilland Canada, Gulfstream, and other manufacturers.

Restrictions apply to non-tolerant aircraft

For aircraft not shown to be radio-altimeter tolerant, the FAA requires operators to revise their aircraft flight manuals before further operations in Canadian airspace.

The limitations prohibit several procedures that rely on radio-altimeter data, including certain special-authorisation ILS approaches, CAT II and CAT III approaches, automatic landings, head-up-display landings to touchdown, and enhanced flight-vision-system operations to touchdown.

For U.S. Part 121 airlines, the requirement is more consequential: aircraft operating in Canadian airspace must be modified to meet the FAA’s radio-altimeter tolerance standard. Aircraft that have already demonstrated compliance with the FAA’s previous 5G tolerance requirements do not require further action under the new directive.

The FAA estimates that the broad rule could affect approximately 1,000 U.S.-registered aircraft. However, it said it does not have definitive data on how many of those aircraft have since received compliant radio-altimeter upgrades or external filters.

Why Canada is changing its 5G protections

Canada introduced a series of safeguards in 2023 as it expanded 5G use in the 3.45-3.90 GHz spectrum range. Those measures included airport exclusion and protection zones, restrictions on the direction of cellular signals near certain runways, and national limits intended to reduce emissions toward aircraft.

According to the FAA, Transport Canada informed the agency in late March that several of those protections would change from July 1. Airport exclusion and protection zones will no longer exist, while the remaining safeguards will protect only aircraft with radio altimeters that meet the required interference-tolerance threshold.

Radio altimeters operate in the 4.2-4.4 GHz band and provide height-above-ground information to several flight-critical systems. The FAA said interference can create false or unreliable data, particularly during approach and landing, increasing flightcrew workload and potentially affecting automation or warning systems.

Boeing aircraft receive additional directives

The FAA also issued parallel, aircraft-specific directives for several Boeing fleets, including the 737 Classic and Next Generation families, older 747 variants, the 747-8, the 777, and the 787.

The 787 directive carries additional relevance because the FAA said unreliable radio-altimeter data can prevent some systems from properly transitioning from air to ground mode after landing. That could affect thrust-reverser deployment, speedbrake deployment, and idle-thrust behavior, increasing landing distance and potentially raising the risk of a runway excursion.

Boeing told the FAA in May that certain configurations within its fleet would not demonstrate tolerance to the new Canadian 5G environment, prompting the type-specific actions.

No broad grounding, but a new compliance test

The directives do not amount to a blanket restriction on airline services to Canada, and the FAA has not identified any current airline cancellations or schedule changes connected to the rules.

Instead, the immediate impact depends on whether an operator’s individual aircraft have already been upgraded or otherwise approved as radio-altimeter tolerant. For compliant fleets, the FAA says no additional action is required.

Still, the measures show that the aviation industry’s 5G-radio-altimeter issue has not disappeared. It has shifted across the border, where Canada’s revised spectrum protections are now forcing regulators and operators to reassess which aircraft can safely use low-visibility and highly automated landing procedures.