Southwest Airlines' planes were grounded nationwide on Tuesday due to what the airline called an intermittent technology issue, causing more than 1,700 flight delays.
The delays come just four months after Southwest cancelled nearly 17,000 flights over the Christmas period due to bad weather and its crew-scheduling system becoming overwhelmed.
The hold on departures was lifted by late morning on Tuesday, shortly after it was announced, but not before traffic at airports from Denver to New York City backed up.
“Southwest has resumed operations after temporarily pausing flight activity this morning to work through data connection issues resulting from a firewall failure,” the Dallas airline said in a statement. “Early this morning, a vendor-supplied firewall went down and connection to some operational data was unexpectedly lost.”
The airline urged customers to check on their flight status “and explore self-service options” for travel as it worked on restoring its operations.
By late morning on the East Coast of the US, Southwest accounted for well over half of all delays nationwide, but the airline had cancelled fewer than a dozen flights, according to FlightAware.
Tuesday's flight freeze was brief, but it adds to the picture of an airline that has struggled more than most with technology issues. Chief executive Robert Jordan has embarked on a campaign to repair the airline's damaged reputation.
The cancellations in December cost the airline more than $1 billion. The Transportation Department is investigating the breakdown.
The airline’s unions said they warned management about problems with the crew-scheduling system after previous problems in October 2021.
Southwest said last month it would add de-icing equipment and increase staffing during winter weather that is so cold it limits the amount of time ground workers can be outside.
