UPDATE The FAA is urging airlines to retrofit or replace older radio altimeters that receive transmissions from outside their authorized frequencies — specifically 5G signals on the nearby C-band. The FAA met Wednesday with telecom and airline industry officials, reports Reuters.
Radio altimeters are authorized to use the 4.2 to 4.4 GHz band, while 5G C-band licenses are for 3.7 to 3.98 GHz. Some older altimeters can’t filter out the C-band emissions.
The FAA, which didn’t comment, wanted to use the gathering to set an achievable timeline for the changes, according to a previously unreported letter reviewed by Reuters. In the document, the FAA asked aviation representatives to offer options and commit to actions to meet the objectives. Retrofitted radio altimeters are in production, according to the FAA. Still to be determined are which planes are most at risk for interference and should be fixed first.
The meeting was also to discuss what should happen after July 5 when the voluntary agreement by the FAA, the FCC, the Transportation Department and AT&T and Verizon expires. The deal restricts 5G signals near certain airports.
The FAA has been holding daily meetings with AT&T and Verizon that it said have “enabled us to closely tailor the areas requiring mitigation while aviation stakeholders take the necessary steps to retrofit existing radio altimeters with antenna filters,” notes Reuters. The FAA said in January it issued authorizations for about 90 percent of the U.S. commercial aviation fleet to perform low-visibility landings at airports where wireless 5G is deployed, reported Inside Towers.
Transportation Secretary Pete Buttigieg recently told the Senate Appropriations Committee that dialogue between all parties is encouraging, and AT&T and Verizon agreed. He acknowledged though, that the altimeter interference problem won’t be resolved by summer, as Inside Towers reported.
By Leslie Stimson, Inside Towers Washington Bureau Chief
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