FAA issues new ruling on 5G interference that may lead to flight delays

Verizon and AT&T are hoping new swaths of C-band cellular radio spectrum will help make the 5G hype closer to reality, but the big mid-band 5G rollout may have a side effect. Airplanes rely on radio altimeters to tell how high they are above the ground to safely land when pilots can’t see, and the Federal Aviation Administration (FAA) is now instructing 6,834 of them to not do that at certain airports because of 5G interference. The FAA ruled on December 7 that those thousands of US planes (and some helicopters) won’t be able to use many of the guided and automatic landing systems that are designed to work in poor visibility conditions if they’re landing at an airport where there’s deemed to be enough interference that their altimeters aren’t reliable. “Landings during periods of low visibility could be limited due to concerns that the 5G signal could interfere with the accuracy of an airplane’s radio altimeter, without other mitigations in place,” said an FAA spokesman. That likely means flight delays: “These limitations could prevent dispatch of flights to certain locations with low visibility, and could also result in flight diversions,” reads the FAA’s written statement. “We are engaged with the wireless operators, as well as our interagency partners, to do everything possible to make sure the mitigations are tailored to prevent disruptions,” an FAA spokesman said.