The airline industry and wireless carriers AT&T (T) and Verizon (VZ) have reached a detente in their showdown over the potential for new 5G antennas to interfere with passenger and commercial flights.

For weeks, the Federal Aviation Administration and stakeholders in the airline industry have faced off over whether the deployment of so-called C-band 5G spectrum will cause radio altimeters in aircraft to malfunction.

That’s an important part of a plane, as it allows it to land in low visibility settings, while still being able to tell how far it is from the ground. But a last minute agreement between the aviation industry and AT&T and Verizon seems to have spared the U.S. from a deluge of flight cancellations just as airlines are trying to recover from COVID-induced slowdowns.

So how did the wireless companies and airlines come so close to disaster?

5G auctions and radio altimeters

Perhaps the most important bit of information about this entire affair is that it’s still safe to fly. While the possibility of 5G interference was real and still exists for some flights, both the airline industry and AT&T and Verizon have come to a temporary agreement to prevent potential hazards.

In fact, the FAA and airlines were set to divert flights or cancel them outright in instances where even the slightest chance of safety issues related to 5G interference was possible.

Frustratingly, this entire incident could have been avoided. The problem kicked off in 2020 when the Federal Communications Commission auctioned off wireless spectrum that would allow AT&T and Verizon to launch improved 5G service across dozens of U.S. markets.

The carriers already have 5G capabilities, but they are either only slightly better than existing 4G LTE speeds or incredibly fast but have limited range. The 5G the carriers snatched up through the $80 billion auction falls into the kind of sweet spot that would offer blazingly fast speeds and extensive range.

Days before the auction, however, the FAA raised concerns that the radio frequencies used in these latest 5G rollouts were too close to those used by aircraft radio altimeters. That could, in theory, cause 5G signals to interrupt an aircraft’s altimeter, hindering its ability to determine how close to the ground it is in low-visibility conditions.

More than a year later, AT&T and Verizon were set to flip the switch on their new 5G networks. But with the radio altimeter matter still in question, the DOT and FAA called on AT&T and Verizon to hold off on deploying their networks.

On Jan. 3 the carriers agreed to halt the rollout for two weeks while the FAA investigated the potential for interference.

Buffer zones and Europe

Since then, AT&T and Verizon have agreed to create buffer zones around airports across the country where they’ll limit their 5G capabilities. According to the latest FAA numbers, some 78% of aircraft, including some of the most popular planes, can fly into locations with those buffers during times of low visibility.

The move has averted what could have been a massive disruption to the airline industry, but could cost AT&T and Verizon, as they need the latest version of 5G to better compete with T-Mobile’s network.

Critics of the decision to hold off on the rollouts frequently point to European airports where 5G is available, and there have been no incidents with radio altimeters.

The FAA, however, says that European cell sites are far different from those used in the U.S. For instance, American towers are pointed out horizontally to maximize range, while some European towers are angled down to avoid interference issues.

American cell sites are also more powerful than their European counterparts, which could increase the chance of disruptions.

The agency also says the buffer zones set up at U.S. airports are actually smaller than those currently in place in Europe.

For now, the FAA and FCC have been given a six-month reprieve during which they’ll need to find a way to ensure that any fears of potential 5G interference are either unfounded or can be worked out with new workarounds.

But if they let the matter simmer for another year or longer, we’ll find ourselves right back at the start of a possible travel catastrophe, with thousands of flights either canceled or delayed. It’s now up to the agency and commission to get to work.

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