The airline 5G mess – where some planes with older radio altimeters could be confused by strong 5G signals when making their final approach to US airports – still isn’t over.
Airlines were given until July 1 to update their fleets, but some won’t meet this weekend’s deadline for three reasons, and their flights will be subject to delay as a result …
The airline 5G mess
If you’re not familiar with the background, it’s a rather bizarre story of an embarrassing clash between two different government agencies.
As satellite TV is essentially no more, the Federal Communications Commission (FCC) decided it made sense to reallocate these frequencies to something else. As they were suitable for 5G use, it auctioned off the rights to use them to mobile carriers. Verizon and AT&T jointly spent $68M on acquiring the rights to what was then labeled 5G C-band.
Another government agency, the Federal Aviation Administration (FAA), appeared to discover this fact after the event. It said that there was a risk of 5G C-band spectrum interfering with radio altimeters.
Radio altimeters on board airliners and some other aircraft bounce a radio signal off the ground and time the return signal to determine the altitude of the plane. This is much more accurate than pressure-based altimeters, and is used during the final approach and landing. It plays an especially important role in conditions of poor visibility, when autoland is used, which relies on very precise readings from radio altimeters.
The FAA had been voicing concerns about the potential risks of C-band interference since 2015, but it seems that the agency didn’t directly communicate these to the FCC until very late in the day.
The result was a very public and embarrassing argument between the two. It did seem clear that only older radio altimeters were at risk, and there was limited evidence even for these. After a series of proposed delays and compromises, a deal was done.
This imposed temporary 5G C-band restrictions at around 50 major airports, and gave the aviation industry until July 1, 2023, to check their older aircraft, updating radio altimeters as required.
Many airliners won’t meet the deadline
The FAA expressed doubts that airlines would be able to update their entire fleets by July 1, proposing to move the deadline back to February 2024. That proposal was rejected, but it now seems the FAA was right.
