As of this writing, the FAA has grounded all outbound domestic flights until at least 9 am ET. It may take longer than that to restore service to its NOTAM system, the on-line platform that all commercial and military pilots must consult before taking off.

The disruption began hours earlier, and the FAA has apparently struggled to overcome it. Savannah Guthrie calls it a “sweeping outage,” and it will almost certainly impact flights for hours even after the FAA restores it:

NEW: The FAA is experiencing a major computer outage that is impacting flights across the country.

All flights in the U.S. were grounded following the incident, a source with knowledge of the situation told @NBCNews.@tomcostellonbc shares the details. https://t.co/z4vajYuIAj pic.twitter.com/0cLdOlG5Mv

— TODAY (@TODAYshow) January 11, 2023

Just when did this outage begin? According to the FAA and Washington Post, it began yesterday afternoon, Eastern Time:

The FAA said the outage began at 8:28 p.m. Universal Time on Tuesday night. It was not immediately clear what caused the glitch. After the system failed, “no new NOTAMs or amendments have been processed,” the FAA said. NOTAM is an acronym for “Notice to Air Missions.”

Universal time, which used to be known as Greenwich Mean Time, runs five hours ahead of Eastern Time. That means the system went down approximately at 3:30 ET yesterday afternoon, and it’s still not up. That in itself raises some interesting questions, to which we’ll return shortly.

The New York Times reported a few minutes ago that the system was “beginning to come back,” but even if it comes up quickly, the cascade effect will reverberate at least all day:

• The F.A.A. ordered airlines to pause all domestic departures until 9 a.m. Eastern time “to allow the agency to validate the integrity of flight and safety information,” it said in a statement. More than 2,500 flights within, into and out of the United States had been delayed on Wednesday, according to FlightAware, a flight tracking service.

• The delays were spread across the country and affected multiple carriers. United Airlines said in a statement that it had temporarily delayed all domestic flights and that it would issue an update when it learned more from the F.A.A. American Airlines said the situation “impacts all airlines” and that it was “working with the F.A.A. to minimize disruption to our operation and customers.”

NBC’s Tom Costello reminded Today viewers of a similar disruption last week, limited to Florida air traffic. That also took several hours to resolve, and thanks to the highly networked commercial air travel system, impacted travel significantly in other areas.

That raises a few questions, among them whether this is a run-of-the-mill computer problem or something else entirely. Was Florida a dry run for a cyberattack, and today the big attack? The White House says they have no evidence that this is an intentional attack on the FAA’s systems, but neither does anyone know what the actual cause of the outage is:

“They don’t know what the cause is,” President Biden told reporters after speaking to Transportation Secretary Pete Buttigieg about the F.A.A. outage. “Aircraft can still land safely, just not take off right now. They don’t know what the cause of it is, they expect in a couple of hours they’ll have a good sense of what caused it and will respond at that time.”

Transportation Secretary Pete Buttigieg spent last week castigating Southwest Airlines for its own systems collapse that stranded travelers. He also appears to be without answers, at least as of a couple of hours ago:

I have been in touch with FAA this morning about an outage affecting a key system for providing safety information to pilots. FAA is working to resolve this issue swiftly and safely so that air traffic can resume normal operations, and will continue to provide updates.

— Secretary Pete Buttigieg (@SecretaryPete) January 11, 2023

Even if this is not a cyberattack — or maybe especially if it’s not a cyberattack — Buttigieg will have some explaining to do. Among the questions will be:

• Is this the same kind of failure that impacted Florida last week?
• What has Transportation done to modernize and strengthen its own systems, especially while lecturing Southwest about their own maintenance and modernization?
• Why is it taking so long to restore and return to normal operation?
• Has Buttigieg even addressed any outstanding issues with this mission-critical NOTAM system until now?
• Why did it take so long for people to be notified of the failure?

Perhaps some answers to these questions will emerge in the next few minutes. We’ll update this post as necessary if they do. Meantime, if you’re flying today, better have your contingency plans at the ready. It’s going to be a loooong day.

Update: Just as a reminder, it’s not like Buttigieg can plead poverty:

more than doubled again…
$15 Billion went to FAA infrastructure.
$5 Billion to Air Traffic Facilities. https://t.co/WZvYPSoOrA pic.twitter.com/Tc1vjkEG1t

— Frog Capital (@FrogNews) January 11, 2023

Update: The FAA lifted the national ground stop a few minutes ago, but it’s not clear whether the NOTAM system has been fully restored or they’re using work-arounds. They reopened two airports without out NOTAM due to “air congestion” prior to ending the ground stop:

Update 5: Normal air traffic operations are resuming gradually across the U.S. following an overnight outage to the Notice to Air Missions system that provides safety info to flight crews. The ground stop has been lifted.

We continue to look into the cause of the initial problem

— The FAA ✈️ (@FAANews) January 11, 2023

Well over 500 flights got cancelled this morning and over three thousand delayed. The snarl in air travel today will be massive. Stay tuned.

Update: It doesn’t appear that NOTAM is functioning yet, at least not fully

This error is displayed when you try to sign in: pic.twitter.com/75NwrW11CW

— Michele Blood (@BloodBrief) January 11, 2023

Foreflight has this notice: FAA NOTAMS ARE NOT UPDATING DUE TO FAA SYSTEM OUTAGE. THIS MESSAGE WILL BE AMENDED WHEN MORE INFORMATION IS AVAILABLE AND REMOVED WHEN FAA UPDATES RESUME.

EffectiveJan 11 2023, 7:22 AM MST

— Gwen Linde (@GwenLinde) January 11, 2023