The U.S. Federal Aviation Administration (FAA) has cleared about 45% of the U.S. commercial plane fleet to perform low-visibility landings at many airports where the new 5G C-Band spectrum will be deployed starting by Wednesday.

The announcement was made on Sunday as the FAA continues its argument with popular telecom giants in the US over the effects of the 5G C-Band spectrum on the altimeter, an instrument used by airplanes to help land easily during low-visibility situations.

For over a month now, there’s been a back and forth between the U.S. passenger and cargo airlines over the effect of the C-Band spectrum on airplanes with the threat to sue if no action was taken against the rollout.

Even as we speak, the majority of airline operators are still sounding the alarm to senior government officials that the issues are far from being resolved and could in fact impact flights and the supply chain.

“Even with the approvals granted by the FAA today, U.S. airlines will not be able to operate the vast majority of passenger and cargo flights due to the FAA’s 5G-related flight restrictions unless action is taken prior to the planned Jan. 19 rollout,” said Airlines for America, a trade group representing American Airlines, Delta Air Lines, FedEx, and other carriers.

The approval includes two radio altimeter models used in many Boeing and Airbus planes which include: Boeing 737, 747, 757, 767, MD-10/-11, and Airbus A310, A319, A320, A321, A330, and A350 models.

The announcement came after telecom giants in the U.S., AT&T, and Verizon plan to continue with the deployment of their new 5G service on Wednesday. The FAA plans to issue more approval over the next coming days.

The FAA said the aircraft and altimeter approvals open “runways at as many as 48 of the 88 airports most directly affected by 5G C-band interference.” But the agency warned that “even with these new approvals, flights at some airports may still be affected.”

According to a Reuters report which cited a 36-page list of the runways covered by the approvals – that is yet to be made public, many larger airports in the country aren’t covered on the list.

The FAA however made it known to Boeing in a letter on Sunday that it was granting approvals for specific runways and planes with certain altimeters “because the susceptibility to interference from 5G C-band emissions has been minimized.”

AT&T and Verizon, which won nearly all of the C-Band spectrum in an $80 billion auction last year, on Jan. 3 agreed to buffer zones around 50 airports to reduce interference risks and take other steps to reduce potential interference for six months. They also agreed to delay deployment for two weeks, averting an aviation safety standoff.

However, the FAA on the other hand previously issued some 1,500 notices detailing the extent of the potential impact of 5G services. “Passengers should check with their airlines if weather is forecast at a destination where 5G interference is possible,” the FAA said Sunday.

Back in early January, the agency also disclosed the 50 U.S. airports that will have 5G buffer zones they include New York City, Los Angeles, Chicago, Las Vegas, Minneapolis, Detroit, Dallas, Philadelphia, Seattle, and Miami.

But airlines warn those buffer zones may not be enough to prevent flight disruptions at those airports.

On Thursday, Airports Council International – North America urged a delay 5G implementation to avoid widespread disruption across the U.S air transportation system.

But a day later on Friday, the FAA said it would require Boeing 787 operators to take additional precautions when landing on some wet or snowy runways.