The radar altimeters aren't "using" (in the FCC sense) any of the 5G spectrum. This is an issue on the receive side. The FCC primarily regulates transmission, and the transmitters themselves are compliant. The FAA's TSO-C87 doesn't have any requirements for rx filtering either. So there's no legal grounds to fine anyone.
That is exactly what's been happening. The FCC has continued with the 5G rollout, and the FAA published a NOTAM prohibiting use of radio altimeters on approach until each model can be proven safe.
However, folks are now unhappy because that means no Cat II/III approaches, which means airliners can't land in fog or bad weather... which means significantly more airline delays while all this gets sorted out and equipment gets recertified or upgraded. Consequences.
(Also, fwiw, the avionics aren't built by Boeing, and this is not a Boeing-specific issue. It impacts other aircraft from all manufacturers.)
It affects Airbus A220, Airbus A330, Boeing 737 and Boeing 787 most notibly.
In that it's mostly a US-issue (Europe has much better protection in this area, i.e. that 5G antenna must be directed downwards, the 787 is the biggest issue, as those are doing international flights with other carriers to US airports.
"...and let the clowns at Boeing and the FAA handle the fallout."
It's NOT their fault!, See my other posts about the ITU, WRC and international radio treaties.
This issue has more to do with Spectrum Management planning failures and goes back as far as the 1980s when governments washed their hands of the matter and 'deregulated' spectrum matters because of commercial pressures. Moreover, they loosened the engineering (interference) specs now we're paying dearly for the fuck-ups.
