Part 2 of 2
Friday, Inside Towers reported how the fractures between the FAA and FCC, airlines and wireless companies developed over years concerning 5G on C-band. Today, we look at what happens next.
At issue is the aviation industry’s fear that 5G transmissions on C-band could potentially interfere with a plane’s radio altimeter that sends out radio waves to determine a plane’s location relative to the ground and other objects. If an altimeter’s waves don’t bounce back because of 5G interference, or can’t be distinguished from other nearby waves, the altimeter could give the wrong reading or not function at all, said Peter Lemme, a former Boeing engineer who spent 16 years at the company designing safety systems that relied on altimeters.
A malfunctioning altimeter, for example, could prompt a plane’s computers to warn pilots about phantom obstacles or prevent systems from warning pilots of real threats, reports The New York Times.
The airline industry has been working on new standards for radio altimeters that would address the 5G interference and other issues. But those standards are not scheduled to be released until October and would apply only to new altimeters.
The most likely solution is to spend hundreds of millions of dollars, or perhaps billions, to fix airplane altimeters and reprogram automatic flight systems. The big question is who pays: airlines or wireless carriers?
“The problem here is because the FAA didn’t have a handle on the extent of the problem” until recently. “It is going to cost someone a boatload of money,” said Harold Feld, a senior vice president at Public Knowledge, a research and advocacy group that has received funding from AT&T and Verizon.
Diana Furchtgott-Roth is a former deputy secretary at the Department of Transportation in charge of researching new technologies, who now teaches transportation economics at George Washington University. She told The New York Times that to fully resolve the issue each plane model has to be tested. “Can’t say the newer ones are going to work and the older ones are not going to work,” she said. “In some cases, it’s the opposite.” The FAA says it has already cleared 62 percent of the U.S. commercial fleet, Inside Towers reported Friday.
The FAA has approved five models of altimeters as 5G compliant, but the approvals are based on the combination of altimeter and plane model. “The most likely solution is to swap out the altimeters,” said Lemme, adding such a swap could take years.
Upgrading altimeters could cost billions of dollars. Airlines do not want to bear that burden, and neither do the wireless companies.
In a Brookings Institution piece last November, former FCC Chairman Tom Wheeler outlined three sources of potential funding: The government could spend some of the $82 billion it received from selling 5G frequencies to the wireless companies; the wireless industry could be forced to pay additional fees for use of those frequencies; or the aviation industry could be forced to pay for the upgrades because it has long known that 5G was coming.
A more immediate solution would be to make permanent the temporary limits that AT&T and Verizon have placed on their 5G networks near airports. Or the companies could reduce the strength of the 5G signals near airports, or redirect antennas in ways that limit or eliminate their impact on planes. These options would probably make 5G networks less useful in those areas, and potentially not available for those who live within the buffer zones of certain airports, according to The Times.
Any solution will have to be negotiated between the airlines and the FAA on one side and wireless companies and the FCC on the other. But the two camps view the problem so differently that reaching agreement could be difficult, said Feld. “The assumptions for how altimeters and 5G towers are going to interact in the real world from each side are radically different,” he said.
By Leslie Stimson, Inside Towers Washington Bureau Chief
Reader Interactions