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Airport disruption: Chaos down to 'new system failure' Airport disruption: Chaos down to 'new system failure'
(35 minutes later)
Widespread disruption at UK airports was caused by a computer system failure "which has not been seen before", National Air Traffic Services (Nats) has revealed.Widespread disruption at UK airports was caused by a computer system failure "which has not been seen before", National Air Traffic Services (Nats) has revealed.
The IT fault at the national air traffic control centre caused problems across the UK on Friday.The IT fault at the national air traffic control centre caused problems across the UK on Friday.
Flights have been returning to normal on Saturday, although almost 40 were cancelled at Heathrow.Flights have been returning to normal on Saturday, although almost 40 were cancelled at Heathrow.
Transport Secretary Patrick McLoughlin said the situation was "unacceptable".Transport Secretary Patrick McLoughlin said the situation was "unacceptable".
In a statement, Nats said in normal operations the number of workstations "in use" versus "in standby" at the Swanwick air control centre fluctuates with the demands of the traffic being controlled.
"In this instance a transition between the two states caused a failure in the system which has not been seen before," it said.
"The failure meant that the controllers were unable to access all of the data regarding individual flight plans which significantly increases their workload."
The glitch caused many delays at Heathrow and Gatwick on Friday, where departing flights were grounded for a time.
Dozens of arrivals and departures at airports across southern England, and as far north as Aberdeen and Edinburgh, were delayed and cancelled.
On Saturday, Heathrow Airport said 38 flights due to arrive or take off before 09:30 GMT had been cancelled but the subsequent schedule was "back to normal".
A Heathrow spokesman said the cancelled flights could not be rescheduled because the airport ran at 98% capacity. He said passengers would be rebooked on other services.
British Airways said there may be "some disruption" to its Heathrow flights on Saturday.
It said Gatwick and London City flights were expected to operate as normal but advised all passengers to check the status of their flight before leaving for the airport.
Gatwick Airport said it would be operating a full service on Saturday although there would be "some backlog".
Stansted said all its flights were running on schedule.
Many other airports are also due to run their scheduled Saturday flights on time, according to their websites.
Swanwick air traffic control centre
Swanwick controls the 200,000 square miles of airspace above England and Wales, cost £623m to build, and employs about 1,300 controllers.
But the facility, which handles more than 5,000 flights every 24 hours, has had a troubled history.
It opened in 2002, six years after its planned commissioning date - a delay which Nats said was due to problems with the software used to power its systems.
Almost a year after it opened, a senior air traffic controller raised concerns with the BBC about health and safety standards and complications with radio communications - which he said cut out erratically.
Technical problems and computer faults hit flights in 2008 and again last summer. And, in December 2013, problems with the internal telephone system then caused further delays.
Friday's problems came a year after a telephone failure at the Hampshire control room caused huge disruption - one of a number of technical hitches to hit the part-privatised Nats since the centre opened in 2002.
BBC correspondent Andy Moore said the issue only lasted for between 30 minutes and one hour but caused chaos because the UK's air traffic control system runs at 99% capacity, giving little scope for managing disruption.
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