Yes, 5G can interfere with airplanes, but it’s unclear whether it will cause ‘harmful interference’

UPDATE (1/18/22): After airline executives urged federal agencies in a letter to withhold 5G deployment within two miles of airport runways for fear of safety issues caused by 5G's potential effects on airplane equipment, the White House announced Verizon and AT&T have agreed to delay 5G deployment near "key airports" until they reach a permanent solution to deployment around airports. The original story continues as written prior to the White House's announcement.

Cellphones have had a turbulent history with airplanes. After all, airplane mode exists for a reason.  

Starting in January 2022, several major cellphone companies plan to begin rolling out more 5G services nationwide. The impending expansion has led to headlines claiming the new technology could interfere with airplanes.

Now, just a few days before 5G's rollout is planned to begin on Jan. 19, a group of airline executives have sent a letter to several federal agencies urging them to withhold implementing 5G within two miles of airport runways for fear of safety issues caused by 5G's potential effects on airplane equipment.

THE QUESTION

Can 5G interfere with airplanes?

THE SOURCES

• Federal Aviation Administration (FAA)
• Federal Communications Commission (FCC)
• Radio Technical Commission for Aeronautics
• Aerospace Vehicle Systems Institute
• Air Line Pilots Association
• CTIA, a cellphone industry lobbying group
• T-Mobile-commissioned analysis of 5G study

THE ANSWER

Yes, 5G can interfere with airplanes. However, exactly how likely that is to happen and how big of an effect it could have is still being studied.

WHAT WE FOUND

The issue with 5G isn’t so much phones, but towers placed near airports. 

In February 2020, the Federal Communications Commission (FCC) decided to make a portion of the electromagnetic spectrum, called C-band frequencies, available for 5G services. A year later, the FCC completed an auction of available frequencies in that range to wireless network providers.

Some providers initially planned to use the newly available C-band frequencies for their 5G networks in December 2021. But the companies put off using the frequencies until January 2022 due to concerns from the Air Line Pilots Association and the Federal Aviation Administration (FAA).

The concerns from the FAA center on a device called an altimeter, which tells pilots how high the plane is off the ground. The instrument is essential for pilots when landing at airports with low visibility.

The C-band frequencies that cellphone providers plan to start using in 2022 operate close to the same frequencies as airplane altimeters.

The FCC considered this when opening C-band frequencies for 5G providers. A study provided to the FCC by the Aerospace Vehicle Systems Institute concluded altimeters are affected by 5G interference. However, a T-Mobile-commissioned analysis disputed some of those conclusions. While the FCC didn’t deny that altimeters could be affected by 5G interference, the agency said it agreed with the T-Mobile-commissioned analysis in that the “study does not demonstrate that harmful interference would likely result under reasonable scenarios.”

The FCC said it expects the aviation industry to “take appropriate action, if necessary, to ensure protection of such devices.”

A 2020 study by the Radio Technical Commission for Aeronautics concluded that there is a “major risk that 5G telecommunications systems… will cause harmful interference to radar altimeters on all types of civil aircraft—including commercial transport airplanes; business, regional, and general aviation airplanes; and both transport and general aviation helicopters.”

So, while there are studies that show 5G could interfere with airplane altimeters, how likely that is to happen and how big of an effect it could have is still being analyzed.

A cellphone industry lobbying group, called CTIA, notes that nearly 40 countries have deployed 5G stations in the C-band. The FAA has also acknowledged “there have not yet been proven reports of harmful interference due to wireless broadband.”

Nonetheless, the FAA has acted upon its concerns. The administration issued a warning in November 2021 about the potential of C-band 5G interference with altimeters and asked operators and manufacturers to assess their equipment.

On Dec. 7, 2021, the FAA issued a directive “prohibiting certain operations requiring radio altimeter data when in the presence of 5G C-band wireless broadband signals.” The agency plans to issue notices when C-band towers are near airports and could affect altimeters.

The Air Line Pilots Association warns that the FAA directive could prevent pilots from landing in low visibility conditions, meaning the number of diversions could increase.

The FAA says it is continuing to work with the FCC and cellphone companies.

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