The US Federal Aviation Administration has issued a new airworthiness directive for Boeing aircraft amid concerns that 5G broadband networks could impact their radio altimeters.
Ottawa established 5G exclusion zones around Canadian airports in 2023, but Transport Canada notified its American counterpart that those protections were ending earlier this week.
“This AD was prompted by a determination that radio altimeters cannot be relied upon to perform their intended function if they experience interference from wireless broadband operations,” the directive states, indicating the change will restrict Boeing 737, 777 and 787 operations at Canadian airports.
The FAA said that the 3.7–3.98 GHz frequency band, otherwise known as the 5G C-Band, has been shown to impact radio altimeters, noting that other airplane systems, including the ground spoiler deployment system, rely on altimeter data to function.
The agency has asked that airplane flight manuals be updated to reflect this risk and “address the unsafe condition on these products.”
The first 5G network in Canada launched in 2020. Today, all major Canadian telecommunications providers operate 5G networks, although availability varies across the country.
According to the Financial Post, Boeing told Transport Canada in May “that certain airplane configurations will not demonstrate tolerance to radio altimeter interference in the new 5G environment in Canada.”
Boeing has not commented publicly on the directive or the elimination of 5G exclusion zones around Canadian airports.
