AT&T and Verizon are slated to activate this new super-fast mobile internet technology nationwide this Wednesday.

But the US aviation authority, the FAA, is concerned about possible interference between the frequencies used by 5G and onboard instruments essential for landing planes under certain conditions and has demanded adjustments.

The FAA has so far validated the use of certain radio altimeter models and given its approval for 48 of the 88 American airports most directly affected by the risk of interference, thus still imposing restrictions in certain cases.

The bosses of ten airline companies on Monday called on authorities to intervene "immediately" to prevent "significant operational disruption to passengers, carriers, supply chains and the delivery of essential medical supplies".

In this context, AT&T and Verizon, which have already postponed the deployment of 5G several times since December, have agreed to temporarily postpone the activation of mobile phone towers around certain airport runways, while maintaining the launch of 5G in the rest of the country.

A 5G logo at the Mobile World Congress in Barcelona, ​​June 29, 2021 Josep LAGO AFP / Archives

AT&T, for example, decided not to activate towers installed within 2 miles (3.2 km) of airports specified by the FAA.

Frustration

The two operators regret, however, that the authorities have taken so long to react to this deployment of 5G, planned for at least two years.

The FAA and the country's airlines "have not been able to solve the problem of 5G around airports even though it has been deployed safely and effectively in more than 40 other countries", pointed out a door. -word of Verizon in a message sent to AFP.

"We are frustrated with the FAA's failure to do what nearly 40 countries have done, which is to safely deploy 5G technology without disrupting air services," AT&T said in a separate message.

The question of the consequences of the deployment of 5G in the United States began to gain momentum in November, after the publication by the FAA of a special bulletin asking the companies concerned to transmit specific information on radio altimeters.

This radar, which measures the distance separating the aircraft from the ground, is essential for night instruments, in particular for landing or in the event of poor visibility.

Certain frequencies allocated for tens of billions of dollars in early 2021 to AT&T and Verizon for the deployment of their 5G, which range from 3.7 to 3.98 gigahertz (GHz), are indeed close to those used by radio altimeters , which operate in the 4.2 to 4.4 GHz spectrum.

If there is no risk of direct interference between frequencies, the transmit power of 5G antennas or some of the upward-pointing emissions could cause problems for some altimeters.

The aircraft manufacturers Airbus and Boeing had also alerted the American authorities in December to these "potential interferences", the United States having for example chosen frequencies closer to those of radio altimeters than in Europe or South Korea.

Ten airlines and carriers such as UPS and FedEx had pointed out in their letter sent Monday to the American government and consulted by AFP that on a day like Sunday, "more than 1,100 flights and 100,000 passengers would be subject to cancellations, detours, or delays "due to the deployment of 5G.

© 2022 AFP