The failure, in the airline’s computer network, forced it to ground flights Sunday night for about three hours. The outage, tied to third-party equipment, yielded about 200 cancelled flights. A replacement is underway.

Alaska Airlines temporarily grounded its fleet late Sunday. It’s a reminder of the threat posed to the sector by tech outages.

Alaska Airlines has revealed that an "unexpected failure" of a critical piece of hardware caused an IT outage that led to its entire fleet being grounded.