Coverage: United flights grounded due to computer issue

United Continental Holdings grounded all of its domestic flights on Sunday evening due to a computer issue.

Ralph Ellis of CNN had the news:

Two sources familiar with the incident told CNN the flights were grounded due to a problem with the communication system that airplanes use to send information to United operations. Aircraft Communications Addressing and Reporting System, or ACARS, is used to record and transmit a range of information, including departure times, as well as weight and balance, which is used to calculate takeoff speeds.

The system outage is an issue for planes that have yet to depart, as pilots need this information to safely take off. Planes already in the air are in no danger, the sources said. The issue does not affect communications between planes and air traffic control.

“Everything has a redundancy, but it’s slow,” said one of the sources. “Putting in flight plans by hand. Not having times automatically recorded or sending weights and such. The ground stop is a way to be incredibly cautious.”

This isn’t the first computer glitch to affect airlines.

Chris Perez of the New York Post reported how angry passengers took to Twitter:

Countless passengers have been taking to social media to alert the public and gripe about the ground stop, which only affected flights in the US.

“They are saying international flights aren’t grounded. So put me on a flight to the Bahamas and I’ll parachute out over tampa. Miss my kids!” wrote one Twitter user.

“Pilot of my @united flight: ‘there is a system-wide computer outage all flights are grounded’ — passengers asked to exit the aircraft,” another tweeted.

Video posted online showed scores of people lined up outside their gates, waiting to board their flights and the ground stop to be lifted.

“What’s going on with this delay from Chicago to Cleveland? Super annoying. 35+ min late and counting,” fumed one flyer, who was supposed to depart earlier in the day, but chose not to.

“Nationwide outage. That’s just great,” she said. “Paid extra for the later flight and this happen.”

Airports across the country were forced to tweet out messages about the technical issues, after receiving loads of complaints.

Alex Johnson and Jay Blackman of NBC News reported that United had bandwidth issues:

All of United Airlines’ domestic flights were grounded for more than two hours Sunday night because of a computer outage, the Federal Aviation Administration said as scores of angry travelers sounded off on social media.

International flights weren’t affected by the ground stop, which the FAA said was issued at United’s request.

“We’re working to get flights on their way,” United said in a statement shortly after 9 p.m. ET. “We apologize for the inconvenience to our customers.”

U.S. officials told NBC News that the Aircraft Communications Addressing and Reporting System, or ACARS, had issues with low bandwidth. No further explanation was immediately available for what United described only as “an IT issue.”