Amsterdam (Reuters) – The aviation industry is in turmoil over the launch of 5G networks in the United States. These can be dangerous because those networks can interfere with the radio altimeter on every aircraft. When landing without good visibility, pilots must rely on those altimeters, but some types of altimeters use the same frequency as 5G networks.

On Tuesday, major US telecommunications companies AT&T and Verizon announced that they would stop publishing around US airports. Earlier this month, they promised to roll out 5G near fifty airports six months later, and now 24 more airports have been added.

Due to this expansion, KLM Airlines has no problem. The Dutch company only flies to major airports where the suspension applies. At other airlines, especially on American flights, 5G problems led to delayed or diverted flights. In some cases, they had to change the schedule to deploy flights that were not affected by the disruptions at airports with 5G.

Multiple frequencies

The United States was not the first country to introduce 5G, but in countries such as France and Japan, the fast mobile network did not pose any security issue. According to the FAA, the US Air Traffic Controller, this is due to the way the network is set up in the United States.

5G has multiple bands. For example, there are well-known frequencies used by earlier mobile data connections such as 3G and 4G. They do not cause any problems. However, with 5G, there is a high frequency band of 3.5 Ghz in terms of frequency, which is the problem. The frequencies for this band have not yet been auctioned off in the Netherlands because the security system’s auditorium in Broom, Friesland still uses that frequency.

Differences

In France, for example, the 3.5 Ghz band enables higher speeds, but its waves reach shorter distances, which is already in use. No problem. The FAA cites this, indicating that there are differences in how the 5G network is structured. For example, American providers prefer to place high-capacity transmission towers. They use 2.5 times more power, so the signals are further extended.

In France, 5G antennas also need to be tilted down so that the waves can reach the ground. In the United States this is not required. Finally, frequencies that are slightly further away from aircraft equipment are also used.

In the near future, the FAA, aircraft manufacturers and manufacturers of altimeters will see if the malfunction actually leads to problems. It is also being explored whether these can be addressed. If that is not possible, the altimeters on many aircraft will have to be replaced.