Several news outlets (here and here) are reporting that the passenger check-in system for United Airlines at Chicago O'Hare airport malfunctioned around 0400 CDT this morning and did not come completely back on-line until 1040 CDT.
Given that: (a) today is the start of the 4th of July holiday weekend in the US, (b) O'Hare is the second busiest airport in the world, and (c) United Airlines is O'Hare's largest tenant, things were a mess at the airport this morning to say the least.
As a result of the computer crash, United ticket agents had to try and check-in outbound passengers by hand (up to 1,000 people stood in check-in lines at one point).
Also, arrving United planes had to sit on the tarmac because United's terminal gates were occupied by delayed departing flights.
In addition, several United flights ended up having to be canceled (interestingly, they did not follow British Airways' example).
Knock-on effects are expected all day long.
Robert N. Charette is a Contributing Editor to IEEE Spectrum and an acknowledged international authority on information technology and systems risk management. A self-described “risk ecologist,” he is interested in the intersections of business, political, technological, and societal risks. Charette is an award-winning author of multiple books and numerous articles on the subjects of risk management, project and program management, innovation, and entrepreneurship. A Life Senior Member of the IEEE, Charette was a recipient of the IEEE Computer Society’s Golden Core Award in 2008.