Garmin Joins Coalition to Protect Radio Altimeters From 5G Interference

Garmin International announced last week that it has joined a broad aviation industry coalition in urging the Federal Communications Commission (FCC) to reconsider its “Report and Order” to repurpose C-band frequency spectrum nearby to the frequency band that is used by safety-critical FAA-certified radio (radar) altimeters, including Garmin’s GRA 5500 and GRA 55. Joining Garmin to express concerns were a coalition of “aviation petitioners” that also included the Aerospace Industries Association, the Aerospace Vehicle Systems Institute, the Air Line Pilots Association, Airbus, Aviation Spectrum Resources, the General Aviation Manufacturers Association, Helicopter Association International, Honeywell International, the International Air Transport Association, and the National Air Transportation Association.

The Aviation Petitioners asked the FCC to reconsider, in part, its March 3, 2020, Report and Order to take into account critical record evidence of the potential for harmful interference to FAA-certified radio altimeters operating in the 4.2 to 4.4 GHz spectrum allocation from prospective flexible use operations in the newly created 3700 to 3980 MHz range.

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 coalition stated 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.”

Authors of the coalition’s petition emphasized that FAA-certified avionics must adhere to a very high established standard. “In the realm of aviation,” the petition stated, “ensuring safety in reasonably likely scenarios to a significant degree is not sufficient: the reality is that FAA-certified avionics tasked with keeping lives safe, such as radio altimeters, are held to standards as stringent as one chance for error in one billion flight hours.”

While the FCC Chairman and the Report and Order both expressly recognize that radio altimeters must operate without harmful interference, the petitioners argue that the FCC has placed the protection of radio altimeters from interference on the industry. “In stark contrast with the draft Report and Order made available to the public by the FCC just three weeks earlier—under which the Commission would have welcomed further studies and promised to take action as appropriate to protect safety-of-life radio altimeters—the FCC has placed the burden solely on the aviation industry to take account of the RF environment that is evolving below the 3980 MHz band edge and take appropriate action, if necessary, to ensure protection of such devices. The Report and Order requires the aviation community to solve any interference problems caused by new entrants who are disturbing the radio frequency environment in which radio altimeters have operated and benefitted the flying public for decades.”