The FAA's nationwide ground stop is over, Wired reported after five hours (an FAA official at the Saturday briefing called it a four-hour stop), but delays continue. At a Saturday news conference, Transportation Secretary Sean Duffy gave a fuller account of what officials believe set it off: a telecom line switch at a remote FAA site. He said the exact fault has not been determined.

Update, Saturday Nov. 14

Duffy spoke at a US Department of Transportation news conference, which the department streamed on YouTube. We read the captions of a broadcaster's rebroadcast of the same conference. Duffy began by saying "here's what we believe happened"; this is what he and the FAA officials with him said:

  • The work. At at least one remote FAA location, a contractor was doing what he called routine maintenance, moving telecom lines from old copper wire to fiber. He said the contractor, L3Harris, is the FAA's legacy provider and owns the network the FAA uses to control airspace.
  • What it did. He said a router being replaced in that work started flooding other routers in the air traffic control system, with over 1,000 connection attempts every four to five seconds. That disrupted communication with aircraft and some radar feeds, he said, and the FAA shut down the airspace for safety.
  • What is not determined. Duffy said officials have not determined whether it was contractor or installer error, or a faulty router: "We haven't determined what the fault was." An FAA official at the briefing said a root-cause analysis is under way and would be shared when complete.
  • Cyberattack. Duffy said officials do not believe it was a cyberattack. Once the work at the remote site was isolated or taken offline, he said, the network came back.
  • Timing. Asked why the work was done at 3 p.m. on a Friday, Duffy said remote locations like this one are done during the day, and that the timing of such work will be re-evaluated.

Friday's account described it differently: Mullin described "putting patches into the system" with new equipment overwhelming the older system. Both accounts are officials' statements; neither is a finished investigation.

Latest status

  • The stop is over. Wired's 8:46 p.m. ET report says the stop lasted five hours. The Verge's headline at 8:53 p.m. ET reads "FAA lifts nationwide ground stop that blocked takeoffs for hours"; we could not open that story. About 9:33 p.m. ET, the FAA's national airspace status page listed no national stop and no ground stop entries of any kind.
  • Delays continue. As of the lift, per Wired citing FlightAware, more than 6,300 flights within, into or out of the US had been canceled and 9,500 delayed. Wired says airlines could need days or weeks to get schedules back on track.
  • The FAA. The FAA's written statement on its newsroom page is dated Friday, is marked preliminary and names no cause. We have seen no written FAA statement on the lift.

What officials have said

Wired reports what Transportation Secretary Sean Duffy and Homeland Security Secretary Markwayne Mullin said at a Friday evening White House briefing:

  • Duffy said "It will take us some time to unwind what has happened." Wired says he blamed "old switches, old routers" and a "data overload," and said a "legacy system" was involved, which Wired reads as likely the FAA's FTI communications network.
  • Mullin said the issue was caused by "putting patches into the system" as new equipment was being installed: "The new technology was overwhelming the older system."
  • Mullin said there were no indications the outage was related to a cyberattack, but "there's not complete certainty right now."

Earlier, CBS News reported the FAA cited "extraordinary circumstances and for reasons of safety" and that the FAA and White House said the issue appeared to be a "telecommunication outage." It quoted Duffy in a social media post: "FAA technicians are investigating the issue."

What was established when the stop began

  • A ground stop was issued. TechCrunch reported that the FAA grounded all flights Friday afternoon, citing "extraordinary circumstances." An FAA spokesperson said the stop followed "communication issues impacting multiple Air Route Traffic Control Centers."
  • The status page. At about 5:36 to 5:37 p.m. ET it showed "Avg. 120 mins. (and increasing) due to other: national stop."
  • Flights in the air. Flights already airborne could land, Wired reported earlier.

What is not established

The cause is not final. Duffy described what officials believe happened and said the exact fault is undetermined (see the Saturday update above). The FAA's own written statement, dated Friday and marked preliminary, gives no cause; it says only that communication issues affected multiple Air Route Traffic Control Centers. Earlier, CBS said, citing multiple unnamed sources, that an update to the private communications network connecting the air traffic control system made it reboot and crash. Wired said that network is run by contractor L3Harris Technologies, whose spokesperson did not respond to its request for comment. We have not found an L3Harris statement. Wired also reported earlier on radio-frequency outages at the Boston, Chicago and New York centers. Bloomberg reported the FBI was examining whether a software update caused the outage, with no cyberattack indicated; we read only that story's headline summary, so treat it as that outlet's reporting.

We also do not know how long recovery will take.

Why it matters

Wired calls it the most disastrous disruption in air traffic since September 11 and says the system is midway through a multi-year network upgrade. For other recent infrastructure failures, see our report on the Microsoft Outlook outage and the iCloud outage.

What we checked

We watched no video; we read the parts of the caption transcript of Duffy's Saturday news conference that cover the cause, the cyberattack question and the timing of the work, the FAA newsroom statement, the Wired lift report in full, the status page at about 5:36 p.m., 7:34 p.m. and 9:33 p.m. ET, and the earlier reports cited above. We saw only the headline of the other lift report. We could not open Secretary Duffy's Friday X post, so his quote there is as CBS gives it. His Saturday X posts did not give a cause. We contacted no one.