A Southwest Airlines plane approaches San Diego International Airport as U.S. telecom companies, airlines and the FAA discuss the possible impact of 5 G wireless services on aircraft electronics in San Diego, California, January 6, 2022. REUTERS Mike Blake
The chief executives of major U.S. passenger and cargo airlines warned of a catastrophic aviation crisis this week, as AT&T T.N and Verizon VZ.N deploy new 5 G services. They said the new C band 5 G service set to begin on Wednesday could render a large number of aircraft unusable, causing chaos for U.S. flights and potentially stranding thousands of Americans overseas.
Here is the background to the dispute:
The United States auctioned mid-range 5 G bandwidth to mobile phone companies in early 2021 in the 3.7 -- 3.98 GHz range on the spectrum known as C band, for about 80 billion dollars.
The new 5 G technology could interfere with instruments like altimeters, which measure how far above the ground an airplane is traveling, according to the U.S. Federal Aviation Administration FAA. Altimeters operate in the 4.2 -- 4.4 GHz range and the concern is that the auctioned frequencies are too close to this range.
Altimeter readouts are also used to facilitate automated landings and to help detect dangerous currents called wind shear.
The FAA's 5 G directives banning the use of radio altimeters at 40 of the biggest U.S. airports was announced last month by United Airlines CEO Scott Kirby.
The directives could disrupt up to 4% of daily flights, according to the U.S. airlines.
Kirby said if left unresolved, it could mean that you could only do visual approaches at major U.S. airports in the event of bad weather, cloud cover or even heavy smog. The faster the service is, the higher the frequency in the spectrum. Operators want to operate at higher frequencies in order to get full value from 5 G.
Some of the C band spectrum auctioned had been used for satellite radio but the transition to 5 G means there will be more traffic.
Verizon and AT&T have argued that C band 5 G has been deployed in about 40 other countries without any aviation interference issues.
They have agreed to buffer zones around 50 airports in the United States, similar to those used in France, for six months to reduce interference risks.
In the European Union in 2019 the standards for mid-range 5 G frequencies in a 3.4 3.8 GHz range were set, a lower frequency than the service set to be rolled out in the United States. The bandwidth has been auctioned in Europe and is currently used in 27 of the bloc's 27 member states.
The issue was specific to the U.S. airspace, according to the European Union Aviation Safety Agency, EASA, which oversees 31 states. There has been no risk of unsafe interference in Europe, it said.
FAA officials have noted that the spectrum used by France 3.6 3.8 GHz is further away from the spectrum 4.2 4.4 GHz used for altimeters in the United States and France's power level for 5 G is much lower than what is authorized in the United States.
Verizon will not use spectrum that is closer to the higher band for several years.
In South Korea, the 5 G mobile communication frequency is 3.42 - 3.7 GHz band and there has been no reports of interference with radio wave since the commercialization of 5 G in April 2019.
There are currently 5 G mobile communication wireless stations in operation near airports, but there have been no reports of problems.
Wireless carriers in nearly 40 countries in Europe and Asia now use the C band for 5 G, with no reported effects on radio altimeters that operate in the same internationally designated 4.2 - 4.4 GHz band, said CTIA, a U.S. wireless trade group, in a filing with the Federal Communications Commission.
AT&T and Verizon agreed to temporarily defer turning on some wireless towers near key airports in the short-term in order to avert a major disruption to U.S. flights. The FAA needs to clear the vast majority of the U.S. commercial aircraft fleet to perform low-visibility landings at many airports where 5 G C-band will be deployed in the long term. This means certifying altimeters to operate near 5 G base stations.