How does 5G pose a threat to the airline industry?

There is a source of the Android Central.

The FAA, the FCC, the President's office, and the Department of Transportation have been warned that the activation of AT&T and Verizon 5G cell sites in close proximity to major airports could lead to a "catastrophic" aviation crisis. It's said that C band 5G service scheduled to begin this week could render a significant number of aircraft unusable and this could lead to stranding tens of thousands of American travelers.

As a precautionary measure, AT&T and Verizon have not activated a number of cell sites that could interfere with airline safety or lead to grounded flights. This information has been known for a while but has never been acted on. It's confusing because none of the actual players is explaining it completely, even though it affects the best phones.

What is happening?

Nick Sutrich is from Android Central.

The C band spectrum in the 3.7 to 3.98 GHz range was auctioned off to carriers for use in 5G networks. The U.S. tightly controls the licensing and usage of radio spectrum. This means that carriers need to lease it. It's worth mentioning that T-Mobile isn't using any of the spectrum in question and that AT&T and Verizon seem to have followed every rule and law in good faith.

It turns out that the range of the aircraft altimeters is between 4.2 and 4.4 GHz. There is a legitimate fear that interference could occur if this is close to a cell transmission site where the signal is more powerful.

It's important that the instruments are used to help detect weather anomalies and assist in the safe landing of aircraft. The FAA would need to ban the use of these instruments at around 40 airports if AT&T and Verizon enabled all of the cell sites that are ready. It means flight disruptions and lost revenue for the airlines.

This is a problem in the U.S. because of the radio spectrum auctioned off. The standards for 5G communications in Europe are in the 3.4 to 3.8 GHz range. There is no potential for overlap because there is enough dead space to act as a buffer.

There is a source of the Android Central.

The broadcast power level for 5G networks in Europe is lower than it would be in the U.S.

The E.U. seems to have solved the issue. South Korea has 5G frequencies between 3.4 and 3.7 GHz and has lower broadcast strength limitations than other countries. The C band spectrum for 5G telecommunications is in use in nearly 40 countries with no reported effects on aircraft equipment.

How to fix it is the bigger question. This isn't a good long-term solution for the immediate future, as the cell sites near airports will need to be halted. It's not changing the frequencies used by aircraft instruments because of an international standard. Lowering transmission power limits or changing the spectrum used for 5G may not be possible without wiping out the progress that has been made with 5G so far.

It's easy to say that better planning could have prevented this. I'm not sure what would be required to make sure there is no radio interference or how to certify new equipment that is still operational, but that may be what is required in the end.