Published online Midwest Flyer Magazine – February/March 2021
AOPA and 14 other aviation associations, urged the Federal Communications Commission (FCC) to suspend a December 8, 2020 auction of spectrum in the 3.7–3.98 GHz band based on a study that found that some telecommunication services pose a “major risk” of interference with aircraft radar altimeter operations.
The chair of the House Committee on Transportation and Infrastructure, Rep. Peter DeFazio (D-Oregon), also called on the FCC to postpone the auction, citing aviation’s concerns. Despite the strong opposition from key leaders in Congress and the aviation industry, the FCC announced December 8 that it had “kicked off” the auction as scheduled.
In a December 7 letter to the FCC, the aviation groups cited a study conducted by the technical standards organization RTCA that “revealed a major risk that 5G telecommunications systems in the 3.7–3.98 GHz band will cause harmful interference to radar altimeters on all types of civil aircraft—including large commercial transport airplanes; business, regional, and general aviation airplanes; and both transport and general aviation helicopters.”
An FCC licensee that gains access to the spectrum through the auction “may provide any services permitted under terrestrial fixed or mobile allocations” under FCC rules, according to an auction summary on the FCC’s website.
In a separate submission to the FCC, the aviation industry offered a variety of potential mitigations to protect radar altimeters from interference from new 5G systems.
Future radar-altimeter technology might complement or supersede some recommended mitigations, they noted—and one way to accelerate deployment of radar altimeters designed to be tolerant of nearby 5G transmissions “would be for the 5G community, as new entrants to the band, to reimburse the affected manufacturers and flight operators in replacing their current radar altimeter systems, once new authorized equipment becomes available.” Specifics, however, were “beyond the scope of this filing.”
