FCC Chair Jessica Rosenworcel has announced plans for the agency to launch a proceeding in April that would explore rules regarding Radio Receivers—not just transmitters, as is currently done

The proposal for a Notice of Inquiry (NOI) is in response to use of sub-standard altimeters in US aircraft. Apparently, some altimeter receivers can be affected by other radio signals several hundred MHz away.

Aircraft altimeters use 4.2 to 4.4 GHz, while new 5G services use completely different frequencies 3.7 to 3.98 GHz, but aviation interests and the FAA have said aircraft at 50 U.S. airports would be vulnerable to the new 5G communications - https://news.northeastern.edu/2022/01/20/5g-rollout-airplane-danger/

Read the full UrgentComm story - https://urgentcomm.com/2022/03/02/rosenworcel-says-fcc-will-consider-receiver-noi-in-april/