5G and aviation: American-American turbulence

The “Verizon-AT&T against the rest of the world” saga has largely animated the news pages of Zonebourse over the past few weeks, and that’s quite normal. After having suffered from Covid, confinements and blockages, shortages or absence of personnel, and unfavorable weather conditions, American air carriers (and logistics players) thought they saw an upturn in the sector from 2022. But 5G has come to wreak havoc on these beautiful recovery plans.

Chaos. Disaster. It is in these terms that the detractors have described what-could-happen if the deployment of ultra-fast mobile Internet technology was carried out near airports within the time frame set by the operators. In anticipation, airlines have therefore canceled hundreds of flights, while receiving official support from aircraft manufacturers Airbus and Boeing. And as a precaution, Verizon and AT&T, the American network giants, have agreed to delay the deployment of relay antennas near the major air hubs of the territory. AT&T notably deactivated the towers installed within a perimeter of 2 miles (3.2 km) around so-called “problem” airports, and Verizon did not put 500 of its towers into service near these same areas.

An interference conflict?

The problem would come from interference between the antennas and the piloting instruments on board. More specifically, the new frequency bands allocated to 5G (band C: from 3.7 to 3.98 GHz) would come into conflict with radio altimeters, i.e. radars that measure using radio waves. the distance between the plane (or helicopter) and the ground, crucial for landing at night or in case of limited visibility. These work with the 4.2 to 4.4 GHz spectrum, which is too close to the spectrum of wireless Internet bands.

According to the telecom operators, there would be no risk of direct interference between these different frequencies. But according to the opposing party, the power of the emissions from the 5G antennas could pose a problem for some of these precision guidance systems, namely distorting their readings, and thus putting the planes and their passengers in danger.

Now, on the one hand, it is up to flight operators and manufacturers to prove to the FAA (the US aviation authority) that their altimeters can perform optimally in a 5G environment. And on the other hand, to the FAA to ensure that no device flies in areas considered dangerous, or operates with unauthorized altimeters. Finally, the authority has issued exemptions: air ambulances, for example, can dispense with the obligation to use an altimeter to continue to operate on all types of tarmacs, and with all types of weather conditions.

What about the rest of the world?

Two questions remain. Why weren’t these issues brought to light and fixed sooner? And why the deployment of 5G in 40 other countries has not had such a negative impact on the local airline industry?

Many countries have assigned 5G bands to their carriers and rolled out the spectrum without any problems. In France, the DGAC (Direction Générale de l’Aviation Civile) has imposed a reduction in the power of wireless Internet signals near airports, heliports and hospitals (which may have helicopter landing zones) , so that they are less powerful than those of aerial radiosondes.

Then, the difference between the frequencies of the radio altimeters and those of the networks is wider in France than in the United States (400 MHz here against 200 across the Atlantic). Thanks to this “buffer” space, the frequencies allocated to telecoms are therefore not in competition with the frequencies reserved for aircraft. France also uses a slower frequency range (from 3.4 to 3.8 GHz). Finally, a safety protocol is added to these measures: the operators must direct the signals from the antennas towards the ground where the air activity is dense. These security zones, added to precautionary zones, have made it possible to avoid the American pitfall on our territory.

Ditto in Europe, the United Kingdom, or even South Korea, where the aviation authorities do not deplore any case of interference between the latest generation of network and navigation systems. Even in Japan, where the 5G band evolves between 4.5 and 4.6 GHz (very close to the frequencies of radio altimeters), the subject does not raise concern.

An American-American problem

As early as March 2020, the FCC (the American Telecom Commission) had expressed its concerns, but, after studying the possible nuisances, quickly swept away a large part of the concerns. At the end of 2020, in turn, the FAA expressed its doubts and requested a postponement of the auction of C-band spectrum from telecom operators. At the time, it was the Trump administration that opposed this last-minute request. The lack of anticipation would then constitute the first cause of this situation.

In addition to the lack of anticipation and coordination on the part of the American authorities, technical details specific to the United States help to explain the current chaotic situation. In the country of Uncle Sam, the antennas would display double the power compared to other global antennas, and would be placed in a vertical position, rather than inclined, according to the President of the Emirates company.

Among the other causes put forward: too many frequencies would have been allocated to the telecommunications industry, including frequencies usually used by the airline sector. Some observers would question the obsolescence of American equipment. Finally, too few altimeter models would have received regulatory approval from the FAA, which has just corrected its copy and brought the approved total to 20 (against 13 previously).

But it seems above all that the subject is financial. Who among telecom operators, aircraft manufacturers, the federal government, authorities, airlines or airport operators has to shoulder the bill for a viable return to service? Between reorienting the antennas, checking the altimeters, or even assigning new frequencies to one or the other, this bill threatens to be salty. American operators have paid exorbitant prices for their frequencies at exorbitant auctions, and are showing little inclination to reopen the portfolio.

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