CAA to review if UK air traffic control is fit for purpose after repeated failures

UK air traffic control faces fresh review after repeated failures

The UK's air traffic control system is under fresh scrutiny after a major software failure on 8 September and a second technical outage at the NATS Prestwick centre less than two weeks later. The Civil Aviation Authority (CAA) has been asked to conduct an independent review, and it will examine whether NATS is set up to deliver a resilient service in future.

The first incident began shortly after 10am on 8 September at NATS' Swanwick centre in Hampshire, which manages most airspace over England and Wales. NATS said a software defect occurred in the flight data processing system while it was dealing with a change of priority for a flight plan. A manual request for an aircraft code was paused because the system received a message for a higher priority activity. When the request resumed, the defect meant it did not resume correctly, and the output was corrupted. The problem lasted a millisecond, but it affected later flight data updates.

The affected data included squawk codes, the four-digit identifiers that allow controllers to track a plane's type, direction, altitude and speed. With less information available, controllers had to limit traffic for safety. The system was restarted and restrictions were applied for about six hours. More than 2,000 flights were cancelled, and more than 300,000 passengers were affected. Airlines UK later said more than 330,000 passengers had been hit and that airlines faced tens of millions of pounds in costs. The disruption cost the sector an estimated £100 million.

NATS chief executive Martin Rolfe apologised and said the fault was not caused by human error or a cyber attack. He said the incident was unrelated to the August 2023 outage, when a faulty flight plan shut down NATS' flight planning system and affected hundreds of thousands of passengers. There was also a radar-related failure in July 2025 that led to about 150 flight cancellations. Ryanair chief executive Michael O'Leary called for Rolfe to resign, saying British air traffic control had suffered repeated collapses. Other airlines, including easyJet, British Airways and Jet2, also questioned NATS' resilience. Rolfe rejected calls to quit, saying his job was to make such failures as rare as possible and to keep passengers safe.

Transport Secretary Heidi Alexander said the issue was not unavoidable. She told the Commons that a cyber attack could be ruled out, ordered the CAA to carry out an independent review, and said it should report within six months. Downing Street said the government had confidence in Rolfe for now. NATS was also told to provide an initial report into the incident, which was published later. It confirmed the millisecond software defect and said the problem was separate from 2023.

The impact on passengers was severe. Travellers slept on airport floors at Heathrow, Stansted and other airports, while others were stranded abroad in Rhodes and elsewhere. Some missed honeymoons, family funerals and medical appointments. Many complained about a lack of information and support. Airlines had a duty of care to provide food, refreshments and hotel accommodation where needed, as well as refunds or rerouting for cancelled flights. But the CAA said passengers were unlikely to be entitled to compensation because the failure was classed as extraordinary circumstances. Travel insurance policies often exclude air traffic control problems.

The CAA review will consider whether NATS' plans to modernise critical systems are adequate, whether recommendations from earlier reviews have been implemented, and what lessons can be learned from other countries. It will also speak to passenger groups. Initial findings are due by the end of January, with a final report by March next year. The transport secretary is expected to meet the chair of NATS in the coming weeks.

The second incident happened at NATS' Prestwick centre in Scotland, which controls airspace over Scotland and parts of northern England. NATS said it was a connectivity issue with part of the system's network. It was reported around 5.30am and engineers fixed it after about five hours. Flights were disrupted at Edinburgh, Belfast City, Belfast International, Manchester, Bristol and other airports. At least 200 flights were cancelled and many more were delayed. NATS said the issue was unrelated to the 8 September software fault, but airlines said enough was enough and renewed calls for Rolfe to go. The transport secretary called the disruption deeply frustrating for passengers. Airports and airlines advised travellers to check with their airline before heading to the airport.