British Airways flights from Britain were delayed on Saturday because of a global system outage, the airline said, with passengers reporting massive hold-ups at airports and planes being held on runways.
"We've found no evidence that it's a cyber attack".
It is not believed that the computer failure was caused by a cyberattack or hackers but this has not lessened the impact. Several hours after problems began cropping up Saturday morning, BA suspended flights up to 6 p.m. (1700GMT) because the two airports had become severely congested. The airline has urged passengers with flights today not to turn up at either of the airports, which are now in chaos.
In September previous year BA apologized to passengers for check-in delays caused by operational glitches that delayed flights at Gatwick and Heathrow, in a repeat of a similar incident that affected London-area flights for the airline last July.
One posted a picture on Twitter of BA staff writing gate numbers on a white board.
Londoner Terry Page, 28, who was booked on a BA flight to Texas, was stuck in a queue in Terminal 5 for two hours. Passenger Phillip Norton tweeted video of an announcement from a pilot to passengers at Rome's Fiumicino airport, saying the problem affects the system that regulates what passengers and baggage go on which aircraft.
Paddy Anigbo, a Nigerian national visiting his wife in the United Kingdom on their wedding anniversary, said his plane sat on the tarmac at Heathrow for about four hours after landing.
BA apologized in a statement for what it called an "IT systems outage" and said it was working to resolve the problem.
There were chaotic scenes at the London terminals as people tried to make their way overseas for the long weekend and half-term school holiday. "We are working to resolve the problem as quickly as possible", a British Airways spokeswoman told CNN via email. Delays could continue into Sunday, but most long-haul flights should be able to land as normal in London.
Airlines depend on huge, overlapping and complex IT systems to do just about everything, from operating flights to handling ticketing, boarding, websites and mobile-phone apps. "I checked in online using the BA app at 8.15 for my flight at 9.25, then went and had breakfast", he said.
In August a power surge near US airline Delta's Atlanta (BSE: ATLANTA.BO - news) headquarters caused computers to crash and led to widespread delays across Delta's entire network.