Norwegian communications regulator Nkom said recent tests of 5G have found no operational effects on the radar altimeters of helicopters. The tests were done at Kjeller Airport in conjunction with the Armed Forces, Defense Research Establishment (FFI), Telenor Research, Telia, the Air Force, the Police Helicopter Service and the Norwegian Air Ambulance. The tests were done on the AW 101 SAR Queen rescue helicopter.
The tests at Kjeller Airport follow reports from interest groups and statements from U.S. aviation authorities that there are indications that radar-based altimeters on planes and helicopters might be affected by 5G signals. Nkom pointed out that most of the frequency band used for 5G in the U.S. is closer to frequencies for altimeters than those used in Norway and elsewhere in Europe.
In the Norwegian tests, a mobile 5G transmitter was placed in the middle of the runway, and a 5G wireless router at the end of the runway exposed the helicopters to continuous 5G signal reception. The various helicopters flew in different patterns around the base station, and were approximately 50 meters from it. In practice, helicopters would normally be much farther from a 5G transmitter than the one tested.
The chaos that unfolded in the U.S. over concerns that 5G signals could interfere with altimeter used in commercial flights was in stark contrast to the lack of stress in Europe. The U.S. operators are using the so-called C-band frequencies, which are somewhat closer to the frequencies used by air navigation equipment than the frequencies used for 5G in Europe.
While the Norwegian tests were carried out on helicopters rather than on planes, they clearly indicate that Norway’s 5G technology will have no ill effect on altimeter function around airports. The 5G networks just launched by AT&T and Verizon in the U.S. operate in the 3.7–3.98 GHz range, whereas altimeters use the 4.2–4.4 GHz range. As the operators have been pointing out, there is actually no overlap, even if the C-band itself does go up to 4.2 GHz.
It appears that poor communication has been a root cause of the problem in the U.S. all along, and if American operators, regulators, and air transportation industry members had worked together as the Norwegians did and made exhaustive tests like this in advance, the crisis might not have happened. It’s impossible to say for sure, but regardless of frequency differences, Norway’s approach to the issue could serve as a model for cooperation.