(CNN) Hundreds of Southwest Airlines flights were delayed after technical problems caused the airline to temporarily suspend operations Tuesday morning.
Southwest said the flight delays were the result of “data connectivity issues resulting from a firewall failure,” an issue that led to a brief ground stop.
Federal Aviation Administration initiated the ground stop at the airline̵[ads1]7;s request, citing “equipment issues.” The ground stop was soon lifted, and in a tweet at 11:35 a.m. ET Southwest said it had resumed operations.
“Early this morning, a vendor-supplied firewall went down and the connection to some operational data was unexpectedly lost,” spokesman Dan Landson said in a statement.
Southwest had delayed 1,820 flights or 43% of its schedule just after noon Tuesday, according to FlightAware. The airline has canceled just nine flights on Tuesday, according to FlightAware. Southwest says its workers “worked quickly to minimize disruption.”
Southwest reported technology issues Tuesday morning and said it would “hopefully resume our operations as soon as possible.”
The FAA said in a statement to CNN that Southwest “asked the FAA to stop the airline’s departures.”
The problems come months after the airline was forced to cancel more than 16,700 flights between December 20 and 29, about half of its schedules during that period. The airline attributed the meltdown in part to changes in staff computer systems. Southwest last month unveiled an “action plan” to prevent another operational meltdown.
Southwest called the latest issue “intermittent technology issues” in a social media post to customers. Several took to social media to complain about delayed flights.
“We apologize for any inconvenience this may cause, but we hope to get everyone up and running ASAP,” the airline wrote in another social media post.
A massive winter storm started the service problems during the holiday season, but Southwest had a much tougher time recovering due to an antiquated crew scheduling system that quickly became overwhelmed, leaving the airline unable to get the crew it needed into locations to operate flights. Almost half of the timetables were canceled during the period from 20 December to 29 December. On some days, as many as 75% of scheduled flights were on the ground.
One of the things that created worse problems at Southwest than at other airlines is that crew members had to call the airline, rather than notify it electronically, to let them know of their availability.