As the Federal Communications Commission nears a planned expansion of radio frequencies available to 5G cellular networks, U.S. aviation industry leaders are expressing concerns about potential safety issues linked to radio (radar) altimeter performance.
Beginning December 5, cellular carriers in 46 U.S. markets are expected to repurpose portions of the C-band frequency spectrum near the frequency band used by safety-critical FAA-certified radio (radar) altimeters.
Safety concerns about potential interference from the FCC’s proposed C-band change have been an issue in the aviation community for more than a year. Last August, these concerns were raised again during a meeting between aviation industry leaders and the FCC.
Representatives of 19 aviation and aerospace companies and associations at the meeting, including Airbus, Boeing, Lockheed Martin, the Air Line Pilots Association and others, released a joint letter afterward that offered details about their concerns.
“…Such harmful interference could lead to an escalation of negative outcomes, from missed approaches, delays, diversions, and flight cancellations, to the shutting down of runways on an indefinite basis,” the letter said.
The letter called on the FCC and the FAA to work together to develop long-term solutions that “allow the 5G industry to advance without inflicting undesired impacts on use of the National Airspace System.”
Reuters on Friday quoted FAA Deputy Administrator Bradley Mims from a letter dated Oct. 6, saying the agency shares his “deep concern about the potential impact to aviation safety resulting from interference to radar altimeter performance from 5G network operations in the C band.”
In a statement to FLYING on Monday, an FAA spokesperson said the “FAA continues to engage with other agencies so that aviation and the newest generation of 5G cellular technology can safely coexist. Safety is the FAA’s top priority.”
An FCC spokesperson, responding to questions from FLYING, said, “Upholding public safety is a top priority for the FCC under the law. We remain committed to ensuring air safety as the agency’s successful track record demonstrates, while moving forward with the deployment of new technologies that support American business and consumer needs.”
The U.S. wireless communications trade association, CTIA, wrote to the FCC in September, insisting the C-band 5G technology is safe for aviation.
“… Several aviation organizations have argued that 5G operations in the C-band will cause interference to radio altimeters that operate 220 megahertz or more away—but they ignore that real-world deployments in the C-band and other nearby bands, both in the U.S. and abroad, operate today without any evidence of harmful interference to altimeters,” CTIA said in the letter. “Moreover, aviation has declined to make available underlying data that would allow all stakeholders to fully evaluate those assertions.”
On its website, CTIA says almost “40 countries are already safely using these and similar radio waves for 5G and other wireless services, at similar power levels. There is no evidence whatsoever of harmful interference with aviation equipment.”
The CTIA website also quotes the European Union Aviation Safety Agency (EASA) as saying, “…we are not aware of any reported occurrence that relates to possible interference originating from 5G base stations.”
The FAA has met extensively about the issue with aviation industry leaders. The agency reportedly is “planning to soon issue a Special Airworthiness Information Bulletin and airworthiness directive about the issue,” according to Reuters.
In the 35-page petition, the coalition stated “radio altimeters are essential to safe airplane and helicopter operations, allowing pilots to safely land and avoid terrain, particularly during poor weather conditions and low visibility. The industry coalition is working to ensure radio altimeters are appropriately protected from prospective flexible-use applications, including 5G operations.”
The petition also said that, “despite assurances by the FCC Chairman to Congress that the C-band Report and Order would be carefully designed so that aircraft are able to use radio altimeters in a continuous and uninterrupted manner, it fails to do so. The industry coalition does not seek to block repurposing the C-band spectrum. Instead, the coalition seeks a path that will make the C-band spectrum available for purposes such as 5G, while ensuring full protection of radio altimeters.”