On Twitter United said, "We have a network outage & are working to get systems back online. We'll update soon."
The system that is affected is used for reservations, ticketing, check-ins. It is not operationally involved with safety of aircraft, but is critical for checking in and, in some cases, boarding passengers. It is expected to have a significant impact on United Tuesday evening as flights will be delayed.
United is working to resolve the issue and minimize any impact to our operations.
