Air Traffic Control Software Glitch Causes Flight Misery Across UK

Thousands of air passengers suffered travel disruption over the weekend after a software failure at an air traffic control centre in Swanwick on Saturday morning caused flight delays and cancellations across the UK.

The National Air Traffic Service (NATS) says normal service has resumed at all affected airports following the glitch, which was fixed by 19:30 on Saturday evening. It was also keen to point out that at no point was the failure a safety risk.

The technical problems related to NATS internal communications system, which has night time and day time configurations. During the night, when traffic is quieter, NATS combines sectors of airspace, while during the day, these sectors are split again.

Technical problems

However the glitch meant it was not possible for the voice communications system to reconfigure these sectors and open up additional control positions, resulting in a significant reduction in UK airspace. By 16:00 on Saturday, NATS said it handled 2,576 flights compared with 2,905 at the same time last week.

Airports in Southern England were the most affected because it is a very complex airspace, with Heathrow forced to cancel 155 flights on Saturday, with 18 more on Sunday, mainly due to crew displacement.

Other hubs affected included Gatwick, Stansted, Manchester, Birmingham, Leeds Bradford, Doncaster Robin Hood, Belfast International, Dublin and Newcastle. According to the BBC, 1,300 European flights were affected, or eight percent of all ait traffic on the continent.

“To be clear, this is a very complex and sophisticated system with more than a million lines of software,” says NATS. “This is not simply internal telephones, it is the system that controllers use to speak to other ATC agencies both in the UK and Europe and is the biggest system of its kind in Europe.

“This has been a major challenge for our engineering team and for the manufacturer, who has worked closely with us to ensure this complex problem was resolved as quickly as possible while maintaining a safe service.”

This is not the first time a systems failure at NATS has led to traffic chaos. In July, technical issues, again at Swanwick,  meant the number of planes flying across the south of England had to be restricted, causing delays to passengers.

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