The Federal Aviation Authority (FAA) and the Federal Communications Commission (FCC) have continued to discuss the deployment of the C-Band 5G network.

AT&T and Verizon bought a C-Band spectrum that lies between 3.7GHz and 4.2 GHz and offers speeds in the 200-800 Mbps for its 5G deployment.

The FAA however warned that these signals could interfere with some altimeters that pilots use to land in conditions with low visibility.

According to the Radio Technical Commission for Aeronautics (RTCA), “Radar altimeters are the only sensor onboard a civil aircraft which provides a direct measurement of the clearance height of the aircraft over the terrain or other obstacles, and failures of these sensors can therefore lead to incidents with catastrophic results resulting in multiple fatalities.”

The interference issue is further complicated by the fact that is no technical standard for altimeters.

Unlike the U.S., Europe was able to successfully deploy C-Band 5G because a spectrum range of 3.4 to 3.8 GHz range was used. This was far from the radar altimeters’ spectrum which lies between 4.2 and 4.4 GHz.

Boeing 717, 737, 747, 757, 767, 777, MD-10/-11, and Airbus A300, A310, A319, A320, A330, A340, A350, and A380 models are safe since they use one of the five approved safe altimeters.

The FAA warned that Boeing 787-8, 787-9, and 787-10 airplanes’ altimeters may not be safe when exposed to C-Band 5G.