Transportation secretary blames ‘routine’ equipment upgrade for grounding flights nationwide

Transportation Secretary Sean Duffy said Saturday that a nationwide ground stop halting flights across the United States was caused by seemingly routine maintenance work.

Duffy said that during "routine maintenance," copper wire at a remote location was being upgraded to fiber optic cable by L3Harris, a longtime contractor for the Federal Aviation Administration. After the upgrade, a router overloaded a critical communication system, leading to the ground stop.

"It's pretty straightforward work that we were doing yesterday at, again, a very remote location," Duffy said during a Saturday press conference that appeared to have technical issues of its own. "What we're working to determine was whether we had incompetence — meaning, was it user error or installator error from L3Harris? Or did they install a faulty router?"

The FAA's acting CTO Rebecca Guy added, "When we started to see the occurrence where our network was having instability, we started to look at what was the cause. And as such, we saw two places that were actually pinging our network at a very high rate — a thousand connections over every four to five seconds."

Guy said the FAA disabled "both of those, right away and were able to stabilize our network," and is now performing a root cause analysis.

Duffy has repeatedly insisted, at multiple press conferences, that Congress needs to provide more funding for aviation equipment upgrades. Asked why the upgrades were made at 3pm on a Friday afternoon — rather than, say, at midnight on a Saturday — he responded that while "switchovers" at bigger airports will take place late at night, remote switchovers happen during the day.

"There will be reevaluation of when we do this work," he said.

This was only the third nationwide ground stop of the 21st century. More than 8,200 flights were canceled on Friday evening, according to aviation data firm Cirium. And the effects continued after the ground stop was lifted, with at least another 3,000 flights canceled on Saturday.

The ground stop came just a day after the FAA announced the rollout of an AI tool for air traffic controllers; the air traffic controllers union said it was not consulted in designing the system. However, FAA administrator Bryan Bedford said the agency sees "zero evidence of anything nefarious and zero evidence of anything AI-related."

"We want to be clear that we have an equipment issue, and we're working through what this defective piece of equipment was," Bedford said.