Investigation launched into air-traffic control meltdown that saw 2,000 flights cancelled

What went wrong with the UK air-traffic control system on 28 August 2023 – and how well or badly did the aviation industry respond to the ensuing chaos?

The Civil Aviation Authority (CAA) has launched an investigation to answer those questions.

On the morning of a Bank Holiday Monday, the computer system used to handle flights to, from and above the UK failed. Twenty seconds later, the back-up system failed due to the same issue: the filing of an anomalous flight plan.

It took some hours for the air-traffic provider, Nats, to solve the problem and restore the system. More than 2,000 flights were cancelled as a result – affecting around 300,000 passengers – and thousands more were delayed.

Nats has issued a preliminary report into the causes of the shutdown. Now the CAA, the organisation that licences Nats, has announced its own review – which will also look at how airlines handled the ensuing chaos.

The investigation, chaired by aviation veteran Jeff Halliwell, will look at the cause of the failure and what has been done to try to prevent it happening again.

But it will also study how Nats communicated with airlines and airports as the chaos unfolded, and whether technical, organisational or cultural factors contributed to the scale of the incident.

Key topics are:

The investigation will also measure how well airlines met their passengers’ rights obligations.

When a carrier cancels a flight at short notice for any reason, it immediately becomes liable for providing suitable alternative transport as soon as possible – as well as finding and paying for a hotel room when necessary. But The Independent knows of many cases in which this did not happen.

With most flights very heavily booked at the end of the summer holidays, many travellers had to pay hundreds or thousands to find a way home, and ran up large hotel bills.

The review will investigate the level of costs travellers were expected to “pay and reclaim” when carriers failed to provide alternative transport and hotels. It will also study how airlines managed vulnerable passengers, who are supposed to get extra care.

Rob Bishton, the CAA’s chief executive, said: “The events of the 28 August bank holiday had a significant impact on many passengers. That’s why we’ve launched this independent review to understand what happened and learn lessons for the future.”

Mr Halliwell said: “It is clear lessons need to be learnt. I am looking forward to working with industry and passengers to tackle this review to really understand how the incident occurred, how it was managed and identify any recommendations.”

The CAA says it could make “changes in the price-control arrangements for Nats” if the review recommends them.

Michael O'Leary, chief executive of Ryanair, told The Independent: “We pay Nats over £100m a year in the UK alone, just Ryanair. Their total income is £750m. And it’s simply not acceptable that you have a complete computer failure.”

In a statement on its website, Nats says: “UK airspace remains some of the most complex and busiest in the world. Nats’ dedicated teams across the entire Nats business diligently and passionately support aviation 24 hours a day, 365 days a year to keep the skies safe.”