The requirement could finally end a dispute between the aviation and wireless industries, which has prevented AT&T and Verizon from fully deploying 5G on the C-Band spectrum licenses the wireless carriers purchased for a combined $69 billion."To minimize the number of erroneous system messages and the unsafe condition they produce, the FAA is proposing to require all airplanes operating under part 121 meet the PSD [power spectral density] performance curve to operate in the contiguous US after February 1, 2024," the notice said.A December 2021 Airworthiness Directive "prohibit[ed] certain operations requiring radio altimeter data when in the presence of 5G C-Band interference."The FCC concluded that harmful interference to altimeters was unlikely to occur "under reasonable scenarios" because of the 220 MHz guard band between 5G and altimeter operations and power limits the FCC required for C-Band transmissions.The altimeter problems spurred the FCC to launch an inquiry into poorly designed wireless devices that receive transmissions from outside their allotted frequencies."