By David Shepardson

WASHINGTON (Reuters] – On Tuesday, the U.S. Federal Aviation Administration granted approvals for new altimeters. These allow around 90% of U.S. Commercial Aviation fleet to land low-visibility at airports with 5G Wireless.

The FAA stated that seven additional aircraft had been cleared, increasing the number of approved altimeters to 20. The FAA had cleared approximately 78% commercial planes as of the end of last week.

AT&T (NYSE:) and Verizon Communications (NYSE: ) On Jan. 18, the company agreed to defer switching new telecom towers close to key airports, while simultaneously turning on the 5G C-Band Service.

Radio altimeters can be used to provide height data above ground in order for bad-weather landings. The 5G technology may cause interference.

It is possible to disrupt landings at smaller airports in bad weather. Alaska Air (NYSE:) Monday’s announcement by the company that “rollout of 5G is still causing disruptions in regional air travel”

According to sources, Verizon has agreed not to turn off 500 towers located near airports temporarily while carriers and administration search for a permanent solution.

Many airlines in the United States are worried about Verizon’s plan to add towers on February 1st. They want to find out if these towers will have an impact on any existing operations. Verizon didn’t immediately respond to our inquiries.

Separately on Tuesday, the FAA issued an airworthiness directive for the Boeing (NYSE) 777- and 747-8 aircrafts. The directive stated interference can affect multiple systems that use radio altimeter data. It does not prohibit operations at large U.S. airfields. Alternative compliance methods have been approved by the FAA for airplanes.

Cleared altimeters are all Boeing 717 and 747 plane models; Embraer 120 and 170 regional jets; All CL600/CRJ regional Jets; DHC-8, ATR turboprops.