Southwest Airlines flights resume after IT issues causes systemwide ground stop

Southwest Airlines briefly halted all of its operations on Tuesday morning, citing "intermittent technology issues."

About 1,800 flights, or 43% of the airline's schedule, were delayed as of 1 p.m. EST according to FlightAware, although that number was expected to increase throughout the day.

A ground-stop order issued by the FAA was lifted shortly before 11 a.m. EST, and Southwest flights began departing airports around the U.S. shortly after.

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The airline said in a statement that an issue with a "vendor-supplied" firewall caused data connection problems within its operations teams. An internal message seen by TPG noted several computer systems that had lost connectivity.

"We ask that travelers use Southwest.com to check flight status or visit a Southwest Airlines Customer Service Agent at the airport for assistance with travel needs," the airline said in a statement, confirming that operations had resumed. "We appreciate the patience of our Customers and Employees during this morning’s brief disruption."

The incident comes as Southwest continues to try and reassure customers, regulators and investors following an operational meltdown during the recent holiday travel period.

That meltdown, which occurred following severe weather that caused delays and cancellations among other carriers as well, was largely attributed to outdated and technology and dated infrastructure that Southwest used to manage various parts of its operation.

In particular, crew scheduling and rescheduling was largely a manual procedure, meaning that agents were forced to reassign pilots and flight attendants onto new flights by hand — a slow, laborious process that stymied the airline's recovery and led to multiple days in a row during which the airline canceled the majority of its flights.

Read more: Wondering what happened to your favorite Southwest route? Here's what to know

Tuesday's incident, in contrast, appeared to be a more run-of-the-mill IT issue of the type that periodically affects most airlines, as well as most other industries that rely on computer networks. The quick resumption of flights suggested that the problem was contained and that even as delays piled up through the day, Southwest could likely complete most of its flights without ultimately canceling them.

Only 11 flights had been canceled as of 1 p.m. EST, less than 1% of the schedule and a routine amount of daily cancellations for an airline of Southwest's size.

Since the holiday meltdown, Southwest executives have said that they were accelerating plans to modernize the airline's systems and doubling down on investments in new infrastructure improvements.

Do you work for Southwest or another airline and have thoughts, tips, or comments to share? E-mail this reporter at david.slotnick@thepointsguy.com.