Planes fight with 5G in the United States

Near the antennas. A commercial plane is about to land in California next to a cell phone pole. / Reuters

The frequency at which the new technology operates in the US causes slight interference in the altimeters of some aircraft when they fly near airports. The State Aviation Safety Agency says that this problem does not occur in Spain, but the pilots distrust

At 30,000 feet all precautions are few; and with 20 seconds left to land, too. The alarms went off at the beginning of the year when the Federal Aviation Administration (FAA), the highest aeronautical authority in the United States, decided to suspend the activation of 5G, the new band in which all mobile phones will operate in the near future, in a number indeterminate number of “priority airports” when detecting a “problem”. They were interferences, initially slight, in some aircraft models in the radio altimeters, a sensor that determines the distance to the ground or any obstacle, which sends signals to other aircraft systems and whose use is essential when flying with reduced visibility.

The episode at the beginning of the year had its immediate translation into a wave of cancellations, diversions and delays. Emirates, Air India, Lufthansa, British Airways… flights that were destined only for airports in the United States.

Why have alerts been triggered only in the United States when 5G is beginning to be a reality throughout the planet? The reason must be found in the fact that the US mobile phone companies are deploying this system in a wave spectrum -from 3.7 to 3.98 gigahertz- very close to that reserved for aeronautical operations. A service for which firms such as AT&T and Verizon paid 81,000 million dollars to the Administration, which if it had to back down now would face a veritable cascade of compensation claims.

The FAA hopes, however, that the blood does not reach the river. It has negotiated with the companies a new postponement so that they implement mitigation systems that reproduce the conditions established in Europe, safer, measures that will be in force for six months at the airports with the greatest impact on the sector. American airlines, for their part, have already warned of the “catastrophic” consequences for aviation and the economy if 5G is extended without additional guarantees.

In Europe there are no such problems when it comes to 5G. At least for now. EASA, the European regulator that oversees civil aviation in a total of 31 countries, has not reported any incidents of interference caused by this reason over the last year. “There is no record” of any problem because the frequency range is much slower, from 3.4 to 3.8 ghz, they report from the State Security Agency (AESA). “The band used for 5G is different from that of the United States, hence the situation is different.”

Given this scenario, the agency refers to the position defended by its European counterpart, for whom “there is no immediate need for risk mitigation actions or for States to act”, a conclusion they have reached after successive rounds of contacts since February 2021 with European aircraft and equipment manufacturers.

“Yes it’s annoying”

However, there are those who disagree. “In some scenarios, the interference can give the aircraft an erroneous indication of the altitude in the vicinity of the runway.” Says Daniel Zamit, from the Union of Air Controllers. “The spectrum of frequencies is limited and that forces us to establish barriers so that they do not interfere with each other.” The problem, he points out, affects not so much the controllers as the pilots, since their link with the planes is limited to the radio and the spectrum they use goes from 118 to 135, far from the range with the which can interfere with 5G. «I would not dare to say that the problem raised is dangerous, but it is annoying. And in a scenario such as the aeronautical one, it is always preferable to err on the side of excess rather than default”, assures Daniel Zamit.

The pilots are the ones who are most critical of the situation that has arisen. Santiago Benítez, deputy director of the Sepla Technical Department, is by no means complacent with the current situation. “What we have in Europe is a false sense that this problem is not with us,” he says. And it refers to a report by the Radiotechnical Commission for Aeronautics that evaluated whether or not these signals affected the altimeters based on where the antennas were placed and the emission powers. «We have in common with the North Americans the section between 3.7 and 3.8 ghz, which falls within the parameters of that study. And he concludes that there is a risk, greater or lesser depending on the type of aircraft ».

The report establishes three categories: large commercial aircraft, passenger and freight; medium-sized, regional and business jets; and the helicopters. “And it turns out that these last two types of aircraft, these interferences affect them very much.” The realization that there is a problem, says Benítez, has led to paralyzing the deployment of 5G in these bands in the United States pending a report that determines the real scope of the problem “and that it has not been finished yet.”

the french model

France is the most cautious country in Europe. Without waiting for the results of the investigation, it has decided preventively and on its own to expand the precautionary zone in its airports where new antennas are not allowed (the last 96 seconds of flight), reduce the power of the signals they emit ( those of the United States, even mitigated, multiply the Gallic parameters by 2.5) and also install them with a slight inclination, oriented downwards, so that they do not interfere with the aircraft signal. All this while the aircraft manufacturers continue to work with the European authorities and the operators to see if the deployment of this new system affects the devices or not. In other words, France has been cured in health and passengers traveling there have reason to “feel safer,” says Benítez.

“The FAA has tested the radio altimeters of several aircraft considering that they are reliable with high-power 5G, but not all of them,” added SEPLA. Its list does not include the Air Nostrum CRJ, the ATR (smaller turboprop aircraft) or the helicopters that carry out rescue missions here. Imagine that any of these devices is making an approach to the airport with a guidance system because the weather conditions are very bad and that an interference falsifies the altimeter reading; which indicates that you can ‘cut’ engines because you are already on the ground, when in fact you are 3 or 4 meters above the ground. The consequences can be very serious.”

Play it from France

Benítez advises, in this sense, to reproduce what France has done while the study currently being prepared is not completed -as the United States is doing, albeit less radical-, because as long as that investigation is not completed we are exposing passengers to a danger that is remote, but it exists.

Meanwhile, the FAA and the phone companies are trying to tie the knots of an agreement that satisfies all parties, since the airlines have submitted a list of up to 50 airports in which they believe that the power of the service of the band in which 5G operates. “Safety is and will always be the top priority for US airlines. We will continue to work with all parties to ensure that the new 5G service can safely co-exist with aviation,” said Nicholas Calio, CEO of Airlines for America.

In a context of pandemic and bad weather, with 10,000 operations suspended since last Christmas Eve, heaven cannot wait. And even less so when the expected recovery of the sector will foreseeably be hampered by the brutal increase in the price of energy products caused by the Russian invasion of Ukraine.