Transportation Secretary Sean Duffy says his department intends to “hold people accountable” for the outage.
The United States’ top transportation official has attributed a rare, hours-long nationwide ground stop by the Federal Aviation Administration (FAA) to maintenance work on an ageing telecommunications network.
Speaking at a news conference in Washington, DC, on Saturday, US Transportation Secretary Sean Duffy described routine work carried out the previous day to replace a router at what he called a “very remote location”, switching it from copper to fibre.
According to Duffy, “contractor error or a faulty piece of equipment” caused that router to flood others across the country’s air traffic control system.
“We had 1,000 connection attempts every four to five seconds,” he told reporters at the Transportation Department.
The resulting disruption to radar feeds and to communications between air traffic controllers and aircraft prompted officials to order a ground stop, he said.
“When we see that, your safety is paramount. We shut down the airspace,” Duffy said.
The Transportation Department identified the contractor responsible for Friday’s maintenance as L3Harris, a US aerospace and defence company contracted to modernise the FAA’s communications infrastructure.
“What we’re working to determine is whether we had incompetence, meaning was it an installer error from L3Harris? Or did they install a faulty router?” Duffy said. “We haven’t determined what the fault was.”
Duffy added that L3Harris, which he said had worked for the FAA for decades, “didn’t meet the moment”.
“They own this network. They’re our prime contractor. I can’t go somewhere else. They own it,” he said. “Or was it a faulty router? And we’re going to find that out. And frankly, we’re going to hold people accountable.”
Al Jazeera has contacted L3Harris for comment on the allegations but has yet to receive a response.
After speculation that Friday’s outage may have been the work of hackers, the US government said on Saturday that it did not “believe” a cyberattack was responsible.
“Once we were able to isolate the work being done at this location, all of our systems came back online,” Duffy said. “So, we don’t believe this was cyber at all.”
The FAA’s administrator, who also addressed Saturday’s briefing, echoed Duffy’s assessment, describing the failure as an equipment error.
“We see zero evidence of anything nefarious, and zero evidence of anything AI-related,” said FAA Administrator Bryan Bedford.
Bedford said a root cause analysis would be released to the public once complete.
As airlines and tens of thousands of passengers work through the fallout from Friday’s stoppage — the longest nationwide halt since the September 11 attacks, and only the second — the FAA said it expects full schedule integrity by the end of Sunday.
“We have crews and aircraft that are out of position for 12,000 flights that were lost,” Bedford said. “These crews, pilots and flight attendants need to get to their points of reconnection with their schedules.”
The agency expects roughly 4,000 to 5,000 of the 41,000 flights scheduled for Saturday to be cancelled, he added.
“That will set us up for a full recovery tomorrow,” Bedford said. “I do think the worst is behind us.”