AT&T and Verizon were to activate the new super-fast mobile internet technology nationwide on Wednesday.

But the US aviation authority, the FAA, is concerned about possible interference between the frequencies used by 5G and those used by onboard instruments essential for landing planes in certain weather 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.

There are therefore restrictions in some cases.

The bosses of ten air transport companies had called on Monday the authorities to intervene "immediately" in order to prevent "a major disruption" of traffic.

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

The FAA expects this to reduce the bulk of cancellations and delays feared by airlines but still anticipates consequences due to limitations with certain radio altimeters, according to industry officials.

Delta said on Tuesday evening "to prepare for the possibility of weather-related cancellations due to the deployment of new 5G services around dozens of American airports as of Wednesday".

United Airlines had recently stressed that it was still awaiting details to understand the impact on its operations.

According to the Wall Street Journal, a few companies based outside the United States, including Japan Airlines, Emirates and Air India, have canceled some flights to the country.

Frustration

President Joe Biden thanked the two operators in a statement for this decision, which according to him avoids "potentially devastating" disruptions to air traffic while allowing the activation of the vast majority of mobile phone towers planned for 5G, essential element for the competitiveness of the country.

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

The two operators regret for their part 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 inability to do what nearly 40 countries have done," AT&T said in a separate message.

The issue began to escalate in November, after the FAA issued a stakeholder bulletin requesting details of radio altimeters, instruments that measure the distance between the aircraft and the ground that can be essential in the event of a poor visibility.

Certain frequencies allocated for several tens of billions of dollars at the beginning of 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 these radars, which operate in the 4.2 to 4.4 GHz spectrum.

If there is no risk of direct interference, the transmit power of the 5G antennas or some of the upward-pointing emissions could cause problems for some altimeters that may be interfered with by these nearby frequencies.

For the president of the American agency in charge of telecoms (FCC), Jessica Rosenworcel, the deployment of 5G “can coexist in complete safety with aeronautical technologies”.

It is now "critical" that the FAA complete its assessment and resolve any outstanding concerns "carefully and expeditiously," it said in a statement.

© 2022 AFP