By David Shepardson

WASHINGTON (Reuters) -Four major U.S. wireless carriers told the Federal Communications Commissions (FCC) late on Friday they had agreed to some voluntary actions to address aviation safety concerns and allow full use of the C-Band wireless spectrum for 5G use.

“These voluntary commitments will support full-power deployments across C-Band, and are crafted to minimize the operational impact on our C-Band operations,” said the letter from Verizon, AT&T, T-Mobile US and UScellular filed with the FCC on Friday and seen by Reuters.

The agreement follows extensive discussions with the Federal Aviation Administration (FAA) and is a major step forward, allowing carriers to increase power levels to get to full C-Band use, according to the letter and people involved in the talks.

Concerns that 5G service could interfere with airplane altimeters, which give data on a plane’s height above the ground and are crucial for bad-weather landing, led to brief disruptions at some U.S. airports last year as international carriers canceled some flights.

Last year, Verizon and AT&T voluntarily agreed to delay some C-Band 5G usage until July as air carriers worked to retrofit airplane altimeters. T-Mobile and UScellular had not begun deployment when the agreement was announced.

Reuters first reported in February that the FAA, Verizon and AT&T were in talks to reach a new agreement that sought to extend some voluntary mitigations beyond July 1.

Verizon said Friday it “agreed to final voluntary commitments that will allow our company to fully use our C-band spectrum for 5G by the previously agreed to deadline of July 1.”

AT&T said the “filing is the result of collaborative and productive conversations with the FAA.”

Some of those commitments could last until 2028. The FAA had initially sought to extend some through up to 2033, two sources briefed on the matter.

The FCC did not immediately comment. The FAA said Friday it continues “to work closely to ensure a safe co-existence in the U.S. 5G C-band environment.”

UScellular said the “agreement results from collaboration and coordination with the FAA, FCC, and our industry partners to ensure UScellular can deploy our C-band spectrum without delay.”

Last month, the world’s biggest airline trade body warned many airlines will be unable to meet looming U.S. deadlines to retrofit airplane altimeters to ensure they are not susceptible to 5G wireless interference.

Wireless carriers won the spectrum in an $80 billion auction with Verizon paying $52.9 billion.

(Reporting by David Shepardson; Editing by Aurora Ellis)

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