The headline of a November 18 article in Ars Technica says it all: “FAA forced delay in 5G rollout despite having no proof of harm to aviation: US delays even as 40 countries use C-band with no reports of harm to altimeters.”
What’s the story here? An interagency squabble between the FAA and the FCC could damage the US ability to implement 5G service, just as the economy is starting to accelerate. 5G provides essential new capabilities for businesses in areas from digital manufacturing to logistics to agriculture. A 2020 PPI report projected that 5G-enabled enterprises could create 4.6 million jobs over the next 15 years, and hundreds of thousands of jobs in the near-term. The Biden Administration must step in and make sure that this issue is settled as quickly as possible, in a way that accounts for safety without holding back growth.
Mobile providers have just spent $80 billion on licenses for what is known as C-band spectrum, which has very desirable characteristics for 5G service, in terms of speed and coverage. The issue is that aircraft altimeters, which measure the altitude of a plane, utilize frequencies that are close to the C-band spectrum used for 5G. Aware of this problem, the FCC put in a large “guard band” of unused spectrum between the 5G frequencies and the altimeter frequencies.
The FAA decided that the FCC’s actions weren’t good enough, and warned of “potential adverse effects on radio altimeters.” This forced Verizon and AT&T to delay their planned roll-out of the new 5G capabilities for at least a month while the agencies duked it out.
But here’s the thing. This C-band spectrum is already in use in 40 other countries which have experienced no problems with altimeters. Moreover, US airlines continue to fly to these countries As Roger Entner wrote, if the interference problem is as dire as the FAA says, “why have the airlines and aeronautics manufacturers not grounded planes” in those countries?
Moreover, the FAA is relying on studies which appear to be using unrealistic assumptions. Based on these assumptions, existing systems would already be interfering with altimeters. For example, Peter Rysavy writes that
Navy radar, such as the AN/SPN-43 radar, operates in mid-band frequencies at extremely high power with ground transmitters pointing at aircraft in geographical areas where U.S. planes operate. Such potential interference, however, has not been a problem in the real world.
This is not the time for agency parochialism. The Biden Administration has to make sure that this problem gets resolved quickly and in accordance with science and good engineering practice.
