Southwest Airlines System-wide Software Outage

Southwest Airlines grounded 250 flights.

Late in the evening of 21 June 2013, a software failure of unreported origin caused a system-wide outage at Southwest Airlines. The outage lasted for three hours, according to news reports,  until 2A Eastern. During this period, 250 flights were grounded. As reported by USA Today, "the glitch impaired the airline's ability to do such things as conduct check-ins, print boarding passes and monitor the weight of each aircraft." A backup system was deployed, according to this source, around 8 pm Pacific time, but it was running much more slowly.