First aircraft-specific limit for 5G signals issued by FAA 

Bloomberg

US aviation regulators published the first aircraft-specific restriction related to new 5G service expected to begin next week, ordering operators of Boeing Co. 787 jets to update landing requirements.
Equipment on the planes that could be subject to interference from 5G radio waves affects how the jet stops after touching down, the Federal Aviation Administration said in an airworthiness directive posted on a government website.
Interference from 5G could result in “degraded deceleration performance and longer landing distance than normal,” the FAA said. The agency is requiring changes to flight manuals and other actions so pilots are aware of the issue.
It’s not clear whether the FAA’s airworthiness directive will dramatically impact flight operations since Boeing can avoid most or all limitations if it can show its equipment is resistant to interference. But the FAA action shows the potential problems that could emerge from the wide range of systems on modern jets vulnerable to the issue.
The frequency of the new wireless service being introduced by AT&T Inc. and Verizon Communications Inc. is located next to radio waves used by so-called radar altimeters and may cause the devices to malfunction, the FAA said in the directive.
The jet’s computers use the altimeter to help determine when it has reached the ground, and that controls multiple functions, including throttles, reverse thrust that helps slow down the aircraft after landing and devices on the wings known as spoilers that improve braking.