United Airlines grounded all its domestic mainline flights on Sunday night due to a computer system problem. A ground stop had been issued and was scheduled to end at 8 p.m., but a little after flights were supposed to resume the airline company tweeted that it was still “working on a resolution.” The Federal Aviation Administration extended the ground stop until 9 p.m. NBC News reported the computer system problem had to do with United’s Aircraft Communications Addressing and Reporting System, which allows planes to communicate with ground stations. While not common, computer glitches have grounded flights before, and as recently as October United customers experienced long delays become of another computer issue. Last summer, computer problems also caused delays for British Airways, Southwest Airlines, and Delta, which had to ground 2,000 flights.
A ground stop is in place for domestic flights due to an IT issue. We’re working on a resolution. We apologize for the inconvenience.— United (@united) January 23, 2017