The FAA on Wednesday approved another three altimeter models for use at airports near cell towers where U.S. telecommunications companies AT&T and Verizon plan to activate the 5G C-band. The new approvals allow for 62 percent of the U.S. commercial fleet to perform low-visibility landings at those airports. As of Monday, the agency had cleared about 45 percent of the fleet to perform low-visibility landings at many of the airports after approving two radar altimeter models installed in a “wide variety” of Boeing and Airbus airplanes. The combination of aircraft and altimeter approval opened runways at as many as 48 of the 88 airports most directly affected by 5G C-band interference, said the FAA. However, international airlines flying affected aircraft models such as the Boeing 777 suspended service to several U.S. cities ahead of an agreement by AT&T and Verizon to delay deployment for the third time.
A new safety buffer announced by the FAA on Tuesday around runways near 5G deployment further expanded the number of airports available to airplanes with previously cleared altimeters to perform low-visibility landings.
In a statement issued Wednesday, the FAA also said it continues to work with manufacturers to understand how various flight control systems use radar altimeter data.
Airplane models with one of the five cleared altimeters include some Boeing 717, 737, 747, 757, 767, 777, and MD-10/-11 models and Airbus A300, A310, A319, A320, A330, A340, A350, and A380 models.
The Boeing 787 remains one model conspicuously missing from the list. The FAA on Wednesday issued an airworthiness directive (AD) for all three variants of the 787 after determining that during landings, certain airplane systems might not properly transition from AIR to GROUND mode when landing on certain runways. As a result, pilots could experience degraded deceleration performance and longer landing distance than normal due to the effect on thrust reverser deployment, speed brake deployment, and increased idle thrust.