Even if you're not a frequent flyer, you've probably heard that Federal Aviation Administration (FAA) of the United States of America and several airlines are claiming that the C-band of the recently approved 5G technology from AT&T and Verizon Wireless will dangerously interfere with the takeoffs and landings of airplanes.
Will this new 5G technology be dangerous? Can you knock a plane out of the sky? Here's what we know:
There are three basic types of 5G:
- Millimeter wave (mmWave): Very fast, up to 1 Gigabit per second (Gbps), but has an extremely short range.
- Midband: Has speeds around 100 Megabit per second (Mbps) and 4G range.
- Low band: It only comes with speeds around 20Mbps, but has a range of tens of kilometers.
Of concern to the FAA and airlines is a new mid-band variation: C-Band 5G.
The piece of spectrum known as C-Band is between 3,7GHz and 4,2GHz and is capable of speeds in the 200-800Mbps range. In the past, it was used for satellite video providers and satellite phone services. AT&T and Verizon bought most of that spectrum for a combined $68 billion. You don't spend that kind of money unless you plan on using it.
Quick note: There is no evidence behind rumors that other types of 5G cause health problems.
What's the deal with C-Band 5G and planes?
The FAA has warned airlines that these signals could interfere with some altimeters that pilots use to land in low-visibility conditions.
According to a report by the Radio Technical Commission for Aeronautics (RTCA) – a non-profit technical organization used by government and industry regulatory authorities – “this frequency band can introduce harmful radio frequency (RF) interference to radar altimeters currently operating in the globally allocated 4,2 to 4,4 GHz aeronautical band. Radar altimeters are deployed in tens of thousands of… aircraft… to support many critical life safety functions of aircraft in various phases of flight."
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The specific concern is that the altimeter radios do not filter out signals from another part of the spectrum, also known as spurious emissions. In short, C-Band 5G interference will prevent the altimeters from working properly.
Shrihari Pandit, co-founder and CEO of New York-based internet provider Stealth Communications, said: "Smaller and older aircraft don't have a filter that allows them to receive only the signals designated for their systems."
Pandit further went on to say, “Radar altimeters are allocated from 4,2 to 4,4 GHz and are based on a radar modulation known as Linear Frequency Modulation… .4,2 GHz.”
This, combined with the altimeters' high receiver sensitivity, means they are very susceptible to interference. To make matters worse, there are, I repeat, no technical standards for altimeters, Pandit said.
The FAA said in a Special Airworthiness Bulletin that airlines and pilots should “be prepared for the possibility that interference from 5G transmitters and other technologies could cause certain safety equipment to malfunction.” This "5G interference with the aircraft's radio altimeter can prevent the engine and braking systems from switching to landing mode, which can prevent an aircraft from stopping on the runway."
Is 5G technology on planes dangerous?
The Federal Communications Commission (FCC) concluded in 2020 that studies warning of this danger “have not demonstrated that harmful interference is likely to result under reasonable scenarios” or even “reasonably foreseeable scenarios”.
Tom Wheeler, visiting fellow at the Brookings Institution and former director of the FCC, said in an article that he doesn't think there is a real technical problem (the article bears the rather alarming title: "The Will 5G mean planes falling out of the sky? ").
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The long-term answer to this problem is to “improve the resilience of future radar altimeter designs to RF interference”. Meanwhile, Wheeler highlighted, “The FCC created a guard band between the 5G spectrum and the avionics spectrum where 5G was prohibited. Boeing, in a according to FCC , had proposed exactly that solution.
What are airlines doing now?
On Monday, major airlines warned that operating commercial networks on C-Band 5G could cause a "catastrophic" aviation crisis. Specifically, it could cripple many wide-body aircraft, "could potentially strand tens of thousands of Americans overseas" and could cause "chaos" for US flights.
Numerous international airlines are no longer operating in the US, including Emirates, Japan Airlines, British Airways, Singapore Airlines, Korean Air and Air India. Some are canceling flights altogether, while others are switching planes.
Emirates chairman Tim Clark told CNN that the airline was not aware of potential 5G rollout issues until the last minute. He called the C-Band 5G situation "one of the most delinquent, utterly irresponsible ones" he has ever seen.
How did Europe manage to roll out C-Band 5G smoothly?
US C-band spectrum and European C-band spectrum are not the same thing. In the EU, C-Band 5G works in the 3,4 to 3,8 GHz spectrum band. This is further away from the spectrum of radar altimeters, which is between 4,2 and 4,4 GHz.
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US President Joe Biden at a press conference on January 19 said: “I… pushed as hard as I could for 5G technology to hold up and fulfill what was being asked by airlines until they could modernize more over the years so that 5G would not interfere with the potential of planes landing. Therefore, any tower with 5G technology within a certain number of miles of the airport should not be operational.”
“My team has been engaging nonstop with mobile operators, airlines and aviation equipment manufacturers to chart a path for 5G deployment and aviation to safely coexist – and, in my direction, they will continue to do so. it until we close the remaining gap and arrive at a permanent and viable solution around these important airports.”
