3:28 p.m. — The FAA computer system that notifies pilots about certain safety issues fails for unexplained reasons.
7:47 p.m. — The agency’s air traffic command center in Warrenton, Va., issues its first public notice of the computer breakdown and sets up an outage hotline.
8:20 p.m. — The FAA issues a fuller notification of the computer failure and says technicians are “working to restore the system.”
6:27 a.m. — United Airlines issues a natiowide ground stop.
7:01 a.m. — Transportation Secretary Pete Buttigieg tweets about the outage.
7:21 a.m. — The FAA announces a nationwide “ground stop,” halting all flights aside from those involving military aircraft and medical evacuations.
7:37 a.m. — The agency terminates the outage hotline.
8:54 a.m. — Buttigieg tweets that ground stop will be lifted, writing that the agency has “determined that the safety system affected by the overnight outage is fully restored.”
9:07 a.m. — The FAA allows full air service to resume. More than 8,500 flights had been delayed and more than 1,200 had been canceled on Wednesday, a backlog that will take hours to resolve.
2:00 p.m. — Buttigieg tells reporters that a backup system went into effect the previous evening, but there were issues in the accuracy of information flowing into the system. FAA called for a reboot of the system at 5 a.m., and the ground stop was put in place until it was verified that the system was operating correctly.