I recently saw an article talking about Delta and how they’re finally updating the altimeters in their planes. They were apparently the last airline to do so and the main reason why carriers were not able to crank cell signals to full power around airports. Is that related?
Yes. The Rockwell-Collins radio altimeter system was lacking a low-pass filter in the transceiver, which was not a necessary item until cellular companies started rolling out 5G networks. Even still, with the highly directional nature and short range of SHF, it was assumed there wouldn’t be interference at first.
During landing, if the right kind of object happened to pass by in the right location at the right time (such as a car driving down a road close to the runway, bouncing a 5G signal upwards as a plane passed over); the radio altimeter would suddenly get a signal that didn’t make sense and kick off the Autoland system, warning the crew who is ready to take over immediately. It’s very likely no passengers ever noticed the transition of controls.
As for the fix, Service Bulletins were issued to check antenna and transceiver models on all aircraft, and replace accordingly. It took my airline a few months to get through all of our planes. We have a very large fleet, and I was even servicing a few aircraft a night myself.
I recently saw an article talking about Delta and how they’re finally updating the altimeters in their planes. They were apparently the last airline to do so and the main reason why carriers were not able to crank cell signals to full power around airports. Is that related?
Yes. The Rockwell-Collins radio altimeter system was lacking a low-pass filter in the transceiver, which was not a necessary item until cellular companies started rolling out 5G networks. Even still, with the highly directional nature and short range of SHF, it was assumed there wouldn’t be interference at first.
During landing, if the right kind of object happened to pass by in the right location at the right time (such as a car driving down a road close to the runway, bouncing a 5G signal upwards as a plane passed over); the radio altimeter would suddenly get a signal that didn’t make sense and kick off the Autoland system, warning the crew who is ready to take over immediately. It’s very likely no passengers ever noticed the transition of controls.
As for the fix, Service Bulletins were issued to check antenna and transceiver models on all aircraft, and replace accordingly. It took my airline a few months to get through all of our planes. We have a very large fleet, and I was even servicing a few aircraft a night myself.
Cool insight. Thanks for sharing.