US aviation regulator FAA has proposed February 1, 2024 as the deadline to adjust the altimeters of a limited number of aircraft to ensure no interference with C-band 5G frequencies.

The new rule requires airlines to provide new altimeters or filters to their passenger and cargo planes by February 1 next year. The The Federal Aviation Administration writes: It is estimated that 180 aircraft require completely new altimeters and 820 aircraft require filters. The total cost was $26 million. There are 7993 aircraft registered in the US registry, so it’s not a huge fraction.

Altimeters work by aiming a signal at the ground and measuring how long it takes for the signal to return. This is about 5G bands ranging from 3.7 to 3.98 GHz. This is close to the frequency range used by aircraft altimeters in the 4.2GHz to 4.4GHz range. The So the FAA was banned The use of ground systems in areas where 5G frequencies disrupt these systems in late 2021 and early last year 3.7GHz-5G launch postponed. These systems are generally used only during periods of low visibility; So flights are not allowed to land under this measure if visibility is poor and 3.7GHz-5G is active.

This problem does not occur in Europe, because other frequencies are used here, i.e. 3.4 to 3.8 GHz. Another factor is that the capacity of modules for 5G is low here, which also contributes to reducing the risk of disruptions. Earlier, the delivery of C-band-5G was also postponed in the Netherlands because the satellite communication company Inmarsat uses the frequency band here. Late last year, the Dutch government made it clear that the 3.5 GHz frequencies for 5G would be used after the summer of this year. Bid.