(Bloomberg) -- For the third time in less than two months, the U.S. aviation system on Tuesday faced the threat of widespread flight disruptions over potential 5G interference, only to get a limited and temporary reprieve.
A last-minute accord between wireless telephone companies and aviation authorities averted major disruptions but didn’t eliminate them -- several carriers warned of potential cancellations beginning Wednesday, when the new 5G service is rolled out.
And Boeing Co. warned operators that one of its most popular long-range jets, the 777 as well as its 747-8 jumbo, might not be allowed to land at some U.S airports, prompting a spate of cancellations.
That happened despite an announcement that AT&T Inc. and Verizon Communications Inc. on Tuesday had agreed to temporarily delay switching on hundreds of 5G cell towers near U.S. airports in talks with government officials designed to limit flight disruptions. The towers broadcast on frequencies adjacent to those used by radar altimeters that help aircraft land in poor weather.
The agreement calls for temporary no-5G buffer zones around airports while federal regulators and industry groups try to reach a permanent solution without repeating the crisis in coming months.
President Joe Biden issued a statement Tuesday praising the delay. “This agreement will avoid potentially devastating disruptions to passenger travel, cargo operations, and our economic recovery, while allowing more than 90% of wireless tower deployment to occur as scheduled,” Biden said.
Talks will continue, he added, “until we close the remaining gap and reach a permanent, workable solution around these key airports.”
The wireless companies paid more than $80 billion for access to the frequency band, allowing them to offer faster 5G mobile-phone services and are anxious to put them to use. The Federal Communications Commission approved the transfer of the frequencies from other uses to the companies last year, concluding there was no threat to aviation safety.
Many details on Tuesday’s agreement haven’t been released, such as the size of the exclusion zones and the specific airports involved. It’s also not clear whether it may be possible for wireless companies to install 5G systems within airports in ways that shield runways while still allowing travelers to use the faster connection.
Airlines on Tuesday night were awaiting details from the Federal Aviation Administration’s evaluation of how the agreement would affect aircraft fleet and runway operations at the airports, two people familiar with the situation said.
Preparations were being made for disruptions. Delta Air Lines Inc., for example, warned of possible cancellations if poor weather occurs in an area where 5G service is turned on and planes have to use the altimeters.
Delta Delays
“Delta is committed to pro-actively communicating with customers whenever possible about a cancellation or delay due to low visibility weather conditions that impact a 5G-affected airport,” the company said in a statement.
And, even with the measures promised by AT&T and Verizon, there may still be restrictions on flights. If certain aircraft have a potential for interference, the FAA may still impose limits on certain types of landings and other flight procedures.
Boeing has alerted operators of the 777 and 747-8 jumbo, its two largest jetliners, that they might not be able to safely land at American airports where 5G signals are present, according to a person familiar with the matter. The bulletin was previously reported by Air Current, a trade publication.
Airlines generally follow such directives by Boeing. American Airlines Group Inc. And United Airlines Holdings Inc., which fly the 777, didn’t comment on the status of 777 flights scheduled Wednesday.
Japan Airlines Co. Ltd. and ANA Holdings Inc., Japan’s two largest airlines, canceled some flights to the U.S. this week and substituted different aircraft for others that were scheduled to be flown on 777s after receiving the bulletin from Boeing. Korean Air Lines Co. announced it had rearranged its fleet on routes to the concerned airports to avoid cancellations.
Altimeter Replacement
The best case scenario for resolving the 5G situation would be if analysis shows that altimeters aren’t at risk from 5G signals, said Peter Lemme, a former aircraft electronics engineer who is a consultant in satellite communications.
“The moving target is exactly what interference levels will be caused,” he said.
That painstaking work is being conducted by aircraft manufacturers along with the FAA and the wireless companies. Until that’s completed, the FAA will have to be cautious and avoid risks, he added.
“The last thing we want to do is find out there was a problem by having an incident,” he said. “That would be unacceptable.”
Longer term, the FAA and the aviation industry have agreed that many or all radar altimeters will have to be replaced. That is a daunting process as well. The industry has been working on developing new standards for the altimeters for two years and it will take several more to get them approved by the FAA and to replace them.
“The best solution is there isn’t any interference,” Lemme said. “But if there is in fact a real problem, it’s going to be ugly.”
©2022 Bloomberg L.P.
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