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Why are airlines squaring off against wireless companies over 5G?

The battle is raging over whether the radio spectrum used by the new wireless service poses a risk to the altimeters of airplanes and helicopters.
A traveler checks his mobile phone while waiting to board a flight to Honolulu at SFO in San Francisco on Oct. 15, 2020.
A traveler checks his phone while waiting to board a flight to Honolulu at San Francisco International Airport on Oct. 15, 2020.Paul Chinn / The San Francisco Chronicle via Getty Images file

The launch of new 5G cellphone service in the United States on Wednesday has sparked a fight between telecommunication companies and the aviation industry, with airlines claiming the high-speed wireless service could interfere with aircraft technologies and could cause "catastrophic" disruptions.

The dispute forced Verizon and AT&T to temporarily limit 5G service around some airports, and airlines scrambled Wednesday to cancel or change flights. But what's the root of the issue? Can 5G service really interfere with airplanes? And what does this all mean for the future of 5G networks in the U.S.?

What is the problem?

Verizon and AT&T are set to roll out 5G wireless services, which offer increased connectivity, higher bandwidth and ultrafast internet speeds. A significant portion of fifth-generation wireless technology, or 5G, operates within a specific range of frequencies that make up what's known as the C-band segment of the radio spectrum. The issue is that this part of the spectrum is near the segment of radio airwaves dedicated to commercial aviation and air traffic operations.

The Federal Aviation Administration has said 5G networks could disrupt aircraft operations. The main concern is that cellular towers and antennas near airports could interfere with radio altimeters, which are electronic devices in aircraft that help pilots gauge their altitude above the terrain. This equipment is particularly important when planes land in poor weather or when helicopters operate at low altitudes.

"The problem is that wireless signals are not 100 percent confined to the bands of spectrum they're assigned to," said Randall Berry, a professor of electrical engineering at Northwestern University. "The concern here is that signals from the 5G band could leak over into the band that airlines are using and confuse these altimeters."

Verizon and AT&T have said their equipment can be safely deployed without interfering with aircraft operations, but in a letter sent Monday to U.S. transportation and economic officials, the CEOs of major airlines said the 5G rollout could ground flights and strand tens of thousands of Americans overseas.

In response, the telecommunication giants agreed Tuesday to temporarily limit C-band 5G service around some airports as they continue to work with the aviation industry and the FAA.

Is this really cause for concern?

It’s possible, Berry said, but he added that there has not been much credible evidence to suggest that 5G technology poses elevated risks for the aviation industry.

Both AT&T and Verizon have expressed frustration over the recent holdups, saying 5G technology has been safely deployed in about 40 other countries without disrupting aircraft operations.

Aija Leiponen, a professor at Cornell University’s SC Johnson College of Business, said there is some variation in how other countries have regulated the C-band spectrum, but the Federal Communications Commission and similar agencies around the world have investigated potential safety issues with 5G technology.

"We haven't seen any known air traffic safety incidents related to this, and 5G has been rolled out in other countries much faster than in the United States," she said.

Concerns about wireless interference in aviation are hardly new. In-flight cellphone use was once banned in the U.S. and many other countries over fears that cell signals could clash with onboard avionics and other navigation systems. In 2013, the FAA began allowing the use of mobile devices on planes if they are set to “airplane mode,” which shuts off the phone’s ability to transmit radio signals to cell towers.

To reduce the possibility of interference, Verizon and AT&T agreed to maintain buffer zones around at least 50 airports, including major hubs like New York’s John F. Kennedy International Airport and the Los Angeles International Airport. The carriers also agreed to temporarily limit deploying 5G service around certain airport runways.

How did we get here?

In the U.S., the FCC is tasked with regulating how different frequencies in the radio spectrum are used.

Last year, the agency put licenses for C-band spectrum up for auction, and Verizon and AT&T were among the mobile carriers that spent $81 billion to use it to deploy new 5G networks.

In November, the FAA issued a bulletin to aircraft manufacturers and operators, warning that they "should be prepared for the possibility that interference from 5G transmitters and other technology could cause certain safety equipment to malfunction."

Leiponen said 5G networks have been under development for the better part of a decade, offering what seemed like ample time to iron out potential safety issues.

"It's kind of baffling that we're at this point where operators are about to press the button to start the networks and now the aviation industry is hitting the brakes and wanting to stop this from happening," she said.

Airline executives and the FAA said they have attempted to raise issues about 5G technology earlier, but those concerns were largely ignored. The back-and-forth has put the two industry sectors at odds with one another and dealt yet another hurdle to the airline industry, which is still contending with the aftermath of widespread flight cancellations due to the omicron variant and recent winter storms.

What did other countries do?

In several other countries, the rollout of 5G service has been far more seamless than the current situation in the U.S.

In France, for instance, regulators limited the power of 5G antennas and restricted their height near airports to reduce the possibility of interference.

In Canada, areas around airfields were designated as "exclusion zones" with restricted 5G service. Nearby antennas are also required to be tilted down and away from flight paths to avoid interference with aircraft during landing.

Berry said these examples demonstrate that the aviation and telecommunication industries can work together to safely deploy new technologies.

"There is good evidence that you can use C-band and radio altimeters," he said. "The question now is: Do we have the right rules in place?"