AUSTIN (KXAN) — A Federal Aviation Administration outage early Wednesday morning grounded thousands of flights across the country, a nationwide impact attributed to a computer system glitch, according to a preliminary update from the FAA. Mike Slack, a private pilot and managing partner behind personal injury law firm Slack Davis Sanger, called the incident unprecedented.

How pilots were impacted by the unprecedented widespread grounding

“I’ve never seen anything like this,” he said.

For Slack and fellow pilots, the Notice to Air Mission system is one aviators use to get updates on conditions along a travel route and at a pilot’s destination, such as any construction, closed runways or nearby, unlit towers they need to be aware of.

When there’s a smaller-scale outage or a lack of NOTAM information available, many pilots have experience calling their destination airport for an update on conditions and essential flight information. However, with how dependent commercial airlines are on scheduled flights and crew rest times, any disruptions to the system could have overarching consequences.

“Each time a flight crew times out, that flight crew’s unable to continue [flying] for a period of time until they get their rest. So that not only delays the flight, that means you have to find a substitute flight group to get that airplane to its next destination,” Slack said. “So the domino effect can be very, very significant.”

Slack said Wednesday’s disruptions will likely continue to disrupt commercial airlines at least through the weekend.

As of now, the specifics behind the NOTAM system’s computer glitch aren’t known. President Joe Biden ordered an investigation into the ground stops following an incident briefing from Transportation Secretary Pete Buttigieg, according to reporting from NBC News.

Those next steps are going to be dependent on the severity of the glitch, Slack said. For commercial airlines, Slack said many of them will likely be looking into contingency plans in case there’s another information breakdown in the future.

That will also require an acceptable means of compliance rubberstamped by the FAA, he added, or an alternative means of getting essential flight information if the NOTAM connection disrupts down the road.

From Slack’s experience, he said it’s unclear if the NOTAM system has been upgraded or the evolution of the system over time. With the heightened volume of both airport and passenger data on the system now compared to decades ago, Slack said he anticipates information on any upgrades — or lack thereof — will be of high interest in this case.

At this time, he said there are a lot of unknowns on any longstanding impacts on the travelers, beyond any initial schedule changes as a result of Wednesday’s ground stops. However, Slack said this is a wake-up call for pilots who may have taken for granted the availability of NOTAM system information.

“We all observed that if the NOTAM system goes down, it brings, certainly, scheduled airline operations to a screeching halt,” he said.

How FAA computer outage impacted ABIA flights

United and Southwest Airlines canceled the most flights out of Austin’s airport Wednesday, according to flight tracking website, Flight Aware.

On Wednesday both had canceled 12 percent of their total flights.

Still, Southwest had the more delays and cancellations than any other airline. That’s because more people choose to fly southwest from ABIA, according to airport data.

The airport’s latest travel numbers show from late last year nearly  percent of passengers were flying Southwest.