What a debacle!  Spurious RF emissions from 3.7 - 4Ghz 5G mobile phone towers in the USA are interfering with 4.2-4.4 Ghz Radar Altimeters on large aircraft as they approach airports for landing.

https://www.aviationtoday.com/2021/12/23/faa-issues-new-radar-altimeter-5g-c-band-risk-assessment-request-aviation-industry/

https://edition.cnn.com/2022/01/19/business/emirates-5g-quest/index.html

It's worth noting that in Australia 3.6GHz is the highest frequency for high-powered 5G comms.

For comparison between Australia and some other countries, the following URL shows Australian 5G transmissions top out at 3.7GHz, which makes a larger buffer with the frequencies used by radio altimeters. This is fairly standard internationally, the URL notes,  with India's 5G services go up to 3.6GHz, while Europe and the UK's top out at 3.8GHz.

This URL also notes, according to Australia's CASA, there's been no reports of radio altimeter incidents linked to 5G since the telecommunications technology rolled out in Australia two years ago.

https://www.abc.net.au/news/science/2022-01-19/us-airlines-warn-5g-could-ground-planes-what-about-australia/100763580

The CASA statement https://www.casa.gov.au/no-sign-5g-interference-australia

The FCC and the Govt need their butts kicked in the You Hess of Hey.
https://www.foxbusiness.com/technology/5g-frequency-will-absolutely-not-bring-airplanes-down-former-fcc-chairman

Competent Regulatory bodies have a purpose.

From my local news
"In New Zealand 5G operated in the 3.5GHz band, between 3410 and 3800Mhz, while radio altimeters operated between 4.2 and 4.4 GHz.

The 400MHz buffer was "absolutely huge" and should be more than enough."