SHAFAQNA – The inside of the National Air Traffic Services air traffic control centre at Swanwick, in Hampshire An unprecedented computer systems failure set off the mayhem that caused delays and cancelled flights for thousands of passengers this weekend.
In its first detailed explanation of the computer glitch that led to flight disruptions on Friday, National Air Traffic Services, which operates the UK’s main air traffic control centre at Swanwick, said the problems occurred as more workstations were being brought on line to deal with an increase in traffic.
“In normal operations the number of workstations in use versus in standby fluctuates with the demands of the traffic being controlled,” Nats said in a statement. “In this instance a transition between the two states caused a failure in the system which has not been seen before.”
The computer failure made it impossible for the controllers to access data regarding individual flight plans. Aircraft were prevented from taking off, but those in the air and close to airports were allowed to land during the shutdown that lasted about 35 minutes.
Air passengers faced continued disruption into the weekend even after Nats declared its systems were back to full operational capacity. A spokesman for Heathrow said 38 flights were cancelled before 9.30am on Saturday “as a knock on from yesterday”.
A computer problem at the Swanwick control centre in Hampshire on the south coast, had forced air traffic controllers to stop any flights departing from London’s airports. Some restrictions remained in place as flights began departing from London’s airports again late in the afternoon.
Transport secretary Patrick McLoughlin said the disruption was unacceptable. Parliament’s Transport Committee chair Louise Ellman said Mr McLoughlin will appear before her panel on Monday and will be asked about the incident.
“Any disruption to our aviation system is a matter of the utmost concern, especially at this time of year in the run-up to the holiday season,” he said. Disruption on this scale is simply unacceptable and I have asked Nats for a full explanation of this evening’s incident. I also want to know what steps will be taken to prevent this happening again.”
British Airways said it was working to look after all customers affected at Heathrow, Gatwick and London City. “We anticipate disruption to both departing and arriving aircraft but will do all we can to minimise any impact,” the airline said.
At Heathrow’s Terminal 5, there were motionless queues snaking around the departures area on Friday evening. Some passengers were waiting uncertainly in line for bag drop even when their flights had been cancelled. Many were slumped on the ground but the mood was calm
EasyJet said: “We are currently doing everything possible to understand the implications on our flight schedule for the remainder of the day. It is too early to say how many passengers and flights will be affected.”
London’s airports were forced to ground all departing flights during the glitch on Friday to allow incoming flights to land. Stansted said it had accepted some flights diverted from London City while the restrictions were in place.
Computer software experts have said the problem appears to lie in the age of the systems – some of which date to the 1960s. Nats said the problem was a different type of failure from one that hit Swanwick almost exactly a year ago.
The Swanwick centre controls aircraft travelling through 200,000 square miles of airspace over England and Wales and handles 5,000 flights in every 24-hour period.
It has been beset with problems since it first opened 12 years ago. The last major outage led to almost 300 flights being cancelled and 1,400 delayed over a two-day period.
That failure in December 2013 cost Nats £7.3m and led to the top executives losing part of their annual bonus.