Why is 5G a problem for airlines? Effects explained amid cancellation of flights

Verizon and AT&T had to delay the 5G service rollout in the first week of January after multiple airlines conveyed concerns with the cellular networks. The two telecom giants were ready to expand the 5th generation of mobile networks on January 5. However, they were instructed by the U.S. government to hold off on deployment for two weeks.

Since last year, aircraft manufacturers and airlines have voiced their concerns over the new network's C-Band spectrum and its effect on an airplane's radio altimeter. The compromise as of now has resulted in carriers halting the deployment of the fifth-generation network services around some of the airports.

On Tuesday, January 18, Verizon announced a temporary limit in its services. In a statement, the network carrier mentioned:

"The Federal Aviation Administration (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."

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5G's risk for aircraft - Explained

As per the United States Federal Aviation Administration (FAA), 5G services' radio spectrum, C-band, interferes with an airplane's ability to land safely at airports with low visibility. The spectrum affects the altimeter, which is part of an aircraft's navigation avionics that provides data on the flight's distance to the ground as they land on the runway.

The U.S. telecom carriers are allowed to utilize frequencies ranging from 3.7 to 3.98 GHz for their network's bandwidth. Meanwhile, altimeters operate between a frequency of 4.2 and 4.4 GHz. This may pose an issue with an aircraft set to land at airports with low visibility and with 5G towers nearby.

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Why can't the network carriers change their frequencies?

Network carriers like AT&T and Verizon have paid billions of dollars to acquire the operational rights in the allotted frequencies. Furthermore, the fifth generation of this cellular network is already active, which makes it impossible for carriers to switch to a different frequency.

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FAA clears over 78% of the U.S. Commercial airplanes to be operational

As of January 20, the FAA approved around 13 models of altimeters expected to function correctly even with the fifth-generational network near the airport. These altimeter models are present in numerous operational Airbus, Boeing, and some Embraer airplanes.

This means aircraft with altimeters that the FAA does not approve in this context will not be authorized to land at airports with low visibility and near an operational fifth-generation network.

It is expected that once further models of altimeters are approved, airlines will replace the susceptible altimeters. However, timelines for such upgrades in select aircraft are neither mentioned by the airlines nor the FAA.