Cause of Edinburgh air traffic control failure that hit 41 flights revealed

An air traffic control failure which cancelled or disrupted more than 40 flights at Edinburgh Airport last month was caused by human error, The Scotsman has learned.

Air Navigation Solutions Limited, which provides air traffic control for the airport, said it had happened because the "usual protocol" had not been followed during a system update.

A total of 30 flights were cancelled - 16 departing and 14 arriving - and 11 others were diverted to other airports.

An ANSL spokesperson told The Scotsman: “Our initial findings indicate that a recent system update applied by one of our third-party providers caused the failure, due to an individual human error on their part where the usual protocol was not followed.

“The team in the tower was able to identify and mitigate the issue and was able to resume service within 90 minutes."

Flights were able to resume around 10.40am that day.

ANSL had previously said only that the fault had been caused by a “technical issue” which had affected one of its systems.

Edinburgh Airport, which is the sixth busiest in the UK with more than 16 million annual passengers, declined to comment.

The incident was the third air traffic control fault to affect the airport in two years following two failures caused by another firm, Nats - the former National Air Traffic Services - which also hit much of the UK.

A spokesperson for the UK Civil Aviation Authority (CAA), the aviation regulator, said after the December fault: “There was a failure within the air traffic control support system, leading the air traffic control team to immediately stop all departures and arrivals.

“The air traffic engineering team swiftly recovered the situation and airfield operations were allowed to continue. There were some cancelled flights and some passengers experienced delays.

“We are assured that the operation at Edinburgh remains safe and that appropriate action has been taken and continues to minimise disruption to consumers.”

Rimesh Patel, a member of the Institution of Engineering and Technology and a cyber security consultant, said after the incident: “When local IT issues arise that causes severe disruption, technology leads should look to review their governance, risk and compliance processes to ensure a proactive management approach is in place to pre-empt any disruptions.''

The July 30 glitch was caused by a problem at Nats’ control centre near Southampton in Hampshire, which controls airspace across the southern half of the UK. The northern half is controlled from Prestwick in South Ayrshire.

That forced a reduction in the number of aircraft which could fly in the London control area, with four Edinburgh flights cancelled, one diverted and others disrupted.

A previous Nats failure in August 2023 happened when a flight plan was being processed.

It caused disruption to more than 700,000 passengers, including on more than 200 flights cancelled at Edinburgh, Glasgow and Aberdeen airports.