The Federal Aviation Administration said Tuesday it had approved 90% of the nation’s commercial plane fleet to land when visibility is poor at airports where there is a risk of interference from 5G wireless signals.

The latest approvals, which include more small regional jets and some turboprops, should smooth airline operations, which have faced some disruption since the rollout of new 5G services by Verizon and AT&T last week. But the agency has warned some planes will prove too susceptible to interference to be cleared.

The FAA has been assessing devices called radio altimeters, which use radar to give precise measurements of a plane’s altitude, to determine whether they could give inaccurate readings because of interference from new 5G towers. The towers and radars operate on neighboring airwaves.

“This work has shown some altimeters are reliable and accurate in certain 5G areas; others must be retrofitted or replaced,” the agency said in a post to its website.... Read More: Washington Post