United Back Online After System Outage

United Airlines flights were back to normal Wednesday after a network outage on Tuesday caused more than 500 delayed flights and several cancellations.

A passenger checks in at a United Continental Holdings Inc. kiosk.
Daniel Acker | Bloomberg | Getty Images
A passenger checks in at a United Continental Holdings Inc. kiosk.

United'spassenger reservations system and website were down for two-and-a-half hours Tuesday, leaving passengers temporarily stranded at airports nationwide. United's backup equipment also failed to kick in properly. The airline's parent is United Continental Holdings.

"United's operations are running normally today following yesterday's network outage," company spokesman Charles Hobart tells CNBC.com in an email. "The outage lasted approximately two hours, and as a result we experienced 580 delays and nine cancellations.

"The outage was caused when a piece of communication equipment in one of our data centers failed and disabled communications with our airports and web site," Hobart says. "We have fully redundant systems and we are working with the manufacturers to determine why the backup equipment did not work as it was supposed to," Hobart said in the email.

On Tuesday, passengers took to Facebook and Twitter posting their experiences, including being issued hand-written boarding passes, standing in lines hundreds of passengers long, and being told to call back, when they phoned to get answers.

The recent glitch was another in a long string of technology problems that began when United merged computer systems with Continental's in March.

Consumer Tips During Flight Delays, Outages

As a road warrior, here's what I would have done if I were traveling during yesterday's outage.

First and foremost, I would have printed my boarding pass at home. While I do enjoy the ease of mobile boarding passes on my smartphone, I always have a paper backup for outage situations — whether it be on the airline's side or my own gadget's failure.

Passengers without paper boarding passes who hadn't yet cleared security yesterday were stuck at check-in desks in the main terminal. Being able to get through security opens up my true and tested strategy for getting quicker assistance.

I'm a member of United's airport club, and the customer service desks inside the lounge are always shorter than what you find at check-in counters and in the terminal. If you're not a club member, the price of a day pass can often be justified through time savings and perhaps rebooking on an earlier flight. The rate for a United Club day pass is usually $50. But it's often available on United's website or mobile app for $39.

Finally, I always call while in line at the airport. If the system came back up and passengers ahead of me were beginning to be helped, a phone agent might be able to adjust my reservation allowing me to step out of line and use a kiosk to print my new boarding pass.