5G flight interference is a non-issue in Portugal

  • ECO News
  • 26 January 2022

The risk of 5G interfering with the altimeters of some planes is causing a stir in the US but is a "non-issue" in Europe. ANAC is "monitoring" and TAP has already received guidance.

The risk of 5G interference in aviation is holding back the migration to fifth-generation mobile in the US. The National Civil Aviation Authority (ANAC) is also “monitoring the issue” in Portugal, but believes the problem “does not arise” in the country or in Europe, despite revealing that safety guidelines have already been issued to airlines licensed to fly to the US, including TAP.

“Interference from 5G only arises in the US because the frequency range adopted there is very close to the range of frequencies of the radio altimeters [of some aircraft], which is not the case in Europe,” an official source from ANAC explains to ECO. These instruments are used for landing when there are low visibility conditions, such as fog, for example.

The American fifth-generation networks operate in the band between 3.7 GHz and 3.98 GHz, “closer to the band used by radio altimeters”, which is between 4.2 and 4.4 GHz. In Europe and Portugal, frequencies in the 3.6 GHz range are used, among others, between 3.4 and 3.8 GHz.

ANAC explains that, in fact, the proximity of frequencies used by 5G and aircraft “translates, from a theoretical point of view, into an increased risk for interference to occur, given the operating mode of a radio altimeter system”. This instrument emits a signal from the plane and analyses “the signal reflected on the ground to calculate the distance to it”. If the measurement occurs near 5G stations, altimetry readings could be “wrong”, creating danger on landing.

ANAC says that the European Aviation Safety Agency (EASA) “has already developed a study and concluded that there is no interference from European 5G networks on radio altimeter readings, and has published a SIB [Safety Information Bulletin] addressed to operators with an Air Operator Certificate authorised to fly to the US”. Among these operators is the national airline TAP, the authority reveals.

In short, “to date, there is no known interference affecting radio altimetry systems installed on aircraft,” but ANAC “is monitoring the issue,” it assures.