July 16, 2021
NBAA joined with 20 industry groups and aircraft and avionics manufacturers in alerting leaders of the Departments of Transportation and Commerce to “an imminent safety risk facing the U.S. aviation industry and the general public” from the deployment of new 5G cellular systems across the country, while also acknowledging the wider benefits of the advanced communications technology.
Despite appeals from a coalition of industry groups, in December 2020 the Federal Communications Commission auctioned flexible-use overlay licenses for spectrum in the 3.7–3.98 GHz band, also referred to as the C-band. These frequencies, utilized by 5G networks, are adjacent to those used by radar altimeters in commercial aircraft and helicopters, including many business aircraft.
“Radar altimeters are the only device aboard every aircraft that can directly measure the distance between the aircraft and the ground,” the stakeholders wrote in the July 14 letter to Transportation Secretary Pete Buttigieg and Commerce Secretary Gina Raimondo. The letter continues: “Interference to radar altimeters from 5G signals “can cause lost, inaccurate, or erroneous data from a broad range of avionics, leading even the most well-trained of pilots to take incorrect actions based on hazardously misleading or missing information, which will put the NAS [National Airspace System] and the general public in danger.”
To resolve the issue, the groups urged collaboration between aviation and telecommunications stakeholders to identify mitigations to radar altimeter interference, while preserving the integrity of 5G communications networks that enable high-speed internet and telecommunications service.
“In an effort to demonstrate the aviation industry’s commitment to be part of the solution, within our coalition we formed a Technical and Operations Working Group, comprised of subject matter experts, and have been actively working towards realistic, data-driven approaches to address likely scenarios,” the letter continued. “We urge both departments … to strongly encourage and facilitate the same kind of information sharing from the telecommunications industry.”
Signatories further noted radar altimeters will also be utilized by many next-generation aircraft, including unmanned aircraft systems and electric vertical takeoff and landing vehicles operating at lower altitudes than most crewed aircraft, and predominantly over congested urban areas.
“The aviation industry has analyzed the 5G service rules and firmly believes that these new systems will create a public safety hazard,” the letter stated. “Simply, we will not be able to maintain the current level of public safety without additional support from the Biden-Harris administration and the implementation of short-term mitigations by the cellular industry.”