What Is 5G and Does It Affect Airplanes? Flights Cancelled Over AT&T, Verizon Rollout

Several international airlines cancelled some flights to the United States this week ahead of AT&T and Verizon's 5G wireless rollout over safety concerns associated with the planned deployment of new network services.

Among the airlines affected was Dubai's Emirates, which said it would suspend flights to nine U.S. destinations from January 19 until further notice, while other operators changed the aircraft being used on certain routes into the country.

Cancellations occurred despite the fact that AT&T and Verizon both announced that they will delay turning on some 5G towers near airports.

While a handful of airlines have announced they are resuming some of the flights that were initially affected following the announcements from the two telecoms companies, further cancellations could still occur unless the Federal Aviation Administration (FAA) issues new formal guidance, Reuters reported.

Earlier this week, the CEOs of the largest U.S. airlines and shipping carriers warned of "catastrophic disruption" to services in a letter to Transportation Secretary Pete Buttigieg and other government officials, urging the telecoms companies to halt the deployment of 5G services within two miles of airports.

The cause of concern from the airline industry was the launch of AT&T and Verizon's "C-band" 5G services, which were scheduled to be switched on Wednesday.

What is 5G?

5G is the term used to refer to the fifth generation technology standard for broadband cellphone networks.

Like its predecessor 4G, 5G networks are divided into small geographical areas called "cells." All 5G devices within a given cell connect to the internet and phone network via a local radio antenna.

The main selling point of 5G networks is that they will provide greater bandwidth, enabling faster Internet browsing and higher download/upload speeds.

What Concerns Have Been Raised About Airline Safety in the Unites States?

In the United States, AT&T and Verizon's 5G services that were scheduled for launch on Wednesday utilize frequencies in a portion of the radio spectrum called the "C-band."

The FAA has warned that these frequencies can be close to those used by radar altimeters—an important piece of safety equipment in aircraft—and thus could lead to hazardous interference in some aircraft, with the Boeing 777 among those that have come under the spotlight.

These altimeters use radio waves to provide highly accurate information about an aircraft's height above the ground, and are crucial for landing in poor visibility, for example.

The airlines who cancelled flights this week said they were acting in response to a notice from Boeing that 5G signals may interfere with the altimeter on the 777.

The radio spectrum is a hotly contested resource, with industries vying for use of different slices of it. In the United States, the Federal Communications Commission (FCC) is responsible for regulating the radio spectrum, and the agency has allocated large portions of it for 5G networks.

The C-band portion of the spectrum that AT&T and Verizon use sits in the 3.7-3.98 Gigahertz range, which the telecoms companies paid billions of dollars to use. This is not the whole 5G spectrum, but it is among the most sought-after portions of it—as a rule of thumb, the higher the frequency, the faster the Internet service that can be provided.

However, the FAA believes that the C-band could be too close to the spectrum used by aircraft altimeters, which operate between around 4.2 and 4.4 Gigahertz.

Even if the possibility is small, the FAA warned in November that airlines "should be prepared for the possibility that interference from 5G transmitters and other technology could cause certain safety equipment to malfunction, requiring them to take mitigating action that could affect flight operations."

The FAA and airline groups are concerned that some altimeters that are not functioning properly could be affected by signals from outside the intended spectrum bands. But it is currently not clear how many altimeters will work safely in the 5G environment.

"The agency has made progress during the last two weeks to safely reduce the risk of delays and cancellations as altimeter manufacturers evaluate data from the wireless companies to determine how robust each model is," the FAA said.

"This work has shown some altimeters are reliable and accurate in the 5G areas; others must be retrofitted or replaced."

The AT&T and Verizon Response

The two telecoms companies went ahead with their respective 5G network launches on Wednesday, although they have agreed to temporarily defer switching on certain 5G networks near some 50 major airports in the United States.

The companies say that C-band 5G has been deployed in several countries around the world without reports of interference issues.

In a statement, Verizon said: "As the nation's leading wireless provider, we have voluntarily decided to limit our 5G network around airports. The FAA and our nation's airlines have not been able to fully resolve navigating 5G around airports, despite it being safe and fully operational in more than 40 other countries."

Meanwhile, AT&T said: "At our sole discretion we have voluntarily agreed to temporarily defer turning on a limited number of towers around certain airport runways as we continue to work with the aviation industry and the FAA to provide further information about our 5G deployment, since they have not utilized the two years they've had to responsibly plan for this deployment."

"We are frustrated by the FAA's inability to do what nearly 40 countries have done, which is to safely deploy 5G technology without disrupting aviation services, and we urge it do so in a timely manner. We are launching our advanced 5G services everywhere else as planned with the temporary exception of this limited number of towers."

Differences in Deployment Around the World

The FAA says there are number of differences between 5G deployment in the United States when compared to other countries, such as France and Japan, when it comes to airline safety.

"The U.S. airspace is the most complex in the world, and the FAA holds ourselves and our aviation sector to the highest safety standards," the agency says. "Deployments of 5G technology in other countries often involve different conditions than those proposed for the U.S."

According to the agency, these differences may include lower power levels, antennas that are tilted downward to reduce potential interference to flights, different placement of antennas relative to airfields, and use of frequencies with different proximity to those used by aviation equipment.

CTIA, a trade association representing the wireless communications industry, says nearly 40 countries already "safely" use C-band and similar radio waves for 5G at similar power levels.

"There is no evidence whatsoever of harmful interference with aviation equipment. In fact, in some of these countries, 5G signals use radio waves that are much closer to those used by aviation equipment without causing harmful interference," CTIA says on its website.

The trade association also points out that the FCC, based on the agency's own research, adopted a "substantial protective barrier" that separates 5G C-band signals from aviation signals.

"This separation is more than twice the size of the separation used in networks that exist today in other countries and twice as large as the barrier requested by some aviation organizations in the FCC record."