How will 5G mobile networks in the US really interfere with aircraft

What’s the concern?

  The US Federal Aviation Administration (FAA) has raised concerns that 5G telephone networks will interfere with radio altimeters fitted to some aircraft. Nonetheless, the Federal Communications Commission (FCC) has authorized the roll-out of these networks, including the placement of phone masts near airports.

 The radio spectrum is a public resource, and it is both congested and hotly contested in the US. Nothing goes to waste, and industries lobby hard to secure their portion. Unfortunately, the part of the spectrum set aside for vital aircraft operations sits very close to that assigned to 5G in the US and raises the chance of interference.

 What exactly is 5G?

  In short, it’s the fifth generation of mobile phone technology. A country is divided up into cells, each with a phone mast at its center. 

    There is no single part of the electromagnetic spectrum that 5G occupies. Some countries are using 600 megahertz to 900 megahertz, which isn’t dissimilar to 4G.7 gigahertz, which boosts data speed somewhat. In many cases, a network will use a mix of these.

     Radio altimeters operate in the 4.4 gigahertz band, and the US has set aside a portion of the spectrum right up to the lower band of that for 5G. In the UK, the comparable band ends at 4 gigahertz and in the EU, it ends at 3.

  Have mobile phones caused issues in the past?

   There have been bans on using mobile phones on planes in many countries due to concerns about interference. 

   George Holmes at Resonant Inc.,  because of planning when rolling out the networks. “We’re dealing with very low probabilities but extremely devastating consequences,” he said.

   The Radio Technical Commission for Aeronautics, a US non-profit that advises on technical issues, published a report in 2020 that concluded that the risk is “widespread and has the potential for broad impacts to aviation operations in the United States, including the possibility of catastrophic failures leading to multiple fatalities, in the absence of appropriate mitigations”. 

   Tom Wheeler, a former chairman of the FCC, wrote in a piece for US think tank the Brookings Institution that while there are genuine concerns, the FCC is “constantly being called upon to play referee between various users of spectrum”, and points out that alleged “interference” can also be played to gain a competitive advantage.

 What happens now?

AT&T and Verizon, telecoms companies that run two of the largest cellular networks in the US, were due to turn on their 5G networks on 19 January, having already delayed twice due to safety fears. AT&T has now postponed again, according to a BBC report. 

 “To be blunt, the nation’s commerce will grind to a halt,” says the letter

Who regulates the use of each frequency?

    Most governments have an agency that controls the radio spectrum – in the US, that is the FCC. It warned in November that airlines “should be prepared for the possibility that interference from 5G transmitters and other technology could cause certain safety equipment to malfunction, requiring them to take mitigating action that could affect flight operations”.

   In other countries, this possibility has been mitigated by close cooperation between departments and countries. Phone masts near airports in France were then limited in power, as they were in Canada. The European Union Aviation Safety Agency says it has been working with aircraft makers, airlines and state spectrum regulators to avoid problems, and that “no rise of unsafe interference has been identified in Europe”.