An old copper wire in the bush: why the US had to shut down its airspace

Washington: A routine upgrade to an old copper wire communications network in a remote area of the United States was responsible for bringing the nation’s air traffic to a halt, officials said.

They effectively ruled out a cyberattack or the involvement of any artificial intelligence systems, adding that the decision to order a nationwide ground stop was taken out of “an abundance of caution”.

Speaking at a news conference on Saturday morning (US time), Transportation Secretary Sean Duffy said the instability in the system occurred while telecom contractor L3Harris was undertaking routine maintenance at a remote location to upgrade copper wiring to fibre-optic.

“That router that was being replaced as we switched from copper to fibre started flooding other routers in other air traffic control systems,” he said. “We had over 1000 connection attempts every four to five seconds.”

Those connection attempts began to overwhelm the system, leading to communications issues with airplanes, and disrupted radar feeds. “When we see that, your safety is paramount. We shut down the airspace.”

Officials said they did not yet know whether the initial problem was caused by bad installation work, a wrong configuration or a faulty new router installed in the system.

Duffy said they did not believe any form of nefarious activity was involved. “Once we were able to isolate the work that was being done at that location, all of our systems came back online,” he said.

“This was an FAA [Federal Aviation Administration] system that didn’t meet the moment, a contractor didn’t meet the moment, or equipment didn’t meet the moment.”

FAA administrator Bryan Bedford apologised to the travelling public for the disruption. He said that by the time the ground stop was ordered at 3.45pm Washington time on Friday (Saturday AEDT), about 30,000 of the day’s 50,000 scheduled flights had already landed or were airborne.

Of the 20,000 remaining, 12,000 had to be cancelled – 9000 commercial flights and 3000 private. There were significant flow-on effects into Saturday, with another 4000 or 5000 flights expected to be cancelled, but the system was expected to recover by Sunday, Bedford said.

“We see zero evidence of anything nefarious and no evidence of anything AI-related. We have an equipment issue,” he said.

The incident has put the focus back on the US’ ageing air traffic control infrastructure, which still relies in part on copper wires and floppy disks.

Earlier this month, the FAA announced plans to end the use of floppy disks by the end of 2028. The Enterprise Information Display System would replace four systems that date back to the 1980s.

Bedford said the system was so old (he described it as “1G”) that it was no longer in production and cost about $US1 billion a year just to sustain. Old Cisco 600 routers were constantly being replaced, he said.

“This is probably one of the worst kept secrets in government – that this [communications] system needs to be replaced.”

Last year, Congress appropriated $US12.5 billion ($18.2 billion) for system upgrades, but Duffy had already announced the Trump administration wanted $US30 billion more. He now wants as much as $US50 billion.

“Everyone says they want to do it, and the president is pushing it, but we don’t get the resources,” Duffy said on Saturday. “How long are we going to wait, America and Congress?”

On Friday night at the White House, when a reporter pointed out to Duffy that the Republicans have controlled Congress for the past two years, he asked her which news organisation she was with and suggested she had not covered Donald Trump’s fight for funding.

The major US airlines were still grappling with the fallout on Saturday, with planes and crews out of place from where they would usually be located. Delta encouraged passengers to rebook for Monday if their plans allowed. United Airlines said most flights were operating normally, but some were delayed or cancelled.

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