A software error has been blamed for the radar failure that caused widespread disruption at major UK airports and led to flights being grounded and passengers stranded across the country.
More than 150 flights were cancelled as a result of the outage, which affected airports in London, Manchester and Birmingham, and forced air traffic controllers to temporarily halt all take-offs and landings on Thursday.
The issue was traced to the National Air Traffic Services (Nats) control centre in Swanwick, Hampshire, where radar systems reportedly stopped displaying flights at around 2.30pm.
The fault brought air traffic operations to a halt and led to an emergency shift onto back-up systems.
Speaking on Friday, Transport Secretary Heidi Alexander confirmed there was no evidence of malicious interference. “This was an isolated event and there is no evidence of malign activity,” she wrote on X, formerly Twitter.
“Flights have now resumed and I am grateful to airlines who are working hard to get people to where they need to be. I will continue to receive regular updates. Passengers should check with airlines before travelling.”
Sources told The Times that the radar outage was caused by a “genuine software error”, and that back-up systems worked as intended to restore operations.
“They run a different programme so there is no chance of the same issue happening twice,” the source added.
Despite the fault being resolved within 20 minutes, the disruption it caused has had lasting effects, with ongoing flight cancellations as the system works to return to normal.
At least 16 flights were cancelled at London Heathrow today — following 46 cancellations on Thursday — with insiders saying air traffic control is still operating on back-up systems.
Passengers at several airports were left sleeping on terminal floors, and up to a million travellers may not be entitled to compensation due to the nature of the failure.
Airlines are reportedly demanding answers as to how such a small software glitch could trigger a near-complete shutdown of UK airspace during the peak of the summer travel season. While services are now largely back up and running, delays and disruption are expected to continue into the weekend as airlines clear the backlog.
