A technical fault within the air traffic control system of Nats, the UK's main air traffic control provider, led to significant disruption for thousands of airline passengers. The issue, which occurred on Wednesday, July 30th, involved a radar failure at Nats' Swanwick air traffic control centre in Hampshire and resulted in limitations on the number of aircraft allowed to fly in the London control area to ensure safety. This led to dozens of flight diversions and cancellations, particularly impacting London Heathrow and Gatwick airports, which are two of the world's busiest.
The disruption extended into the following day, with at least 15 additional cancellations at London airports. Major airlines like British Airways, easyJet, and Ryanair were heavily affected. British Airways, which holds more than half of the slots at Heathrow, cancelled 10 outbound and 10 inbound flights on Wednesday, with a further six flights cancelled on Thursday. EasyJet grounded 20 departures from Gatwick on Wednesday. Ryanair cancelled approximately 250 flights on Monday, affecting about 40,000 passengers, and 70 flights on Tuesday due to a similar issue earlier in the week involving an unusual flight plan data that its systems could not process.
The swift recovery of flight operations was hindered by the lack of "slack" in London's air travel system, which handles more airline passengers than any other city globally. Gatwick, the busiest single-runway airport, operates with landings and take-offs as close as 65 seconds apart, while Heathrow is the world's busiest two-runway airport. The incident stranded passengers, with some experiencing delays of up to 20 hours and others, like those on a China Airlines flight, diverted to Frankfurt because the crew ran "out of hours."
Airlines expressed disappointment, with easyJet stating it was "extremely disappointed" by another air traffic control failure. Ryanair's chief operating officer, Neal McMahon, called for the resignation of Nats chief executive Martin Rolfe, criticizing the repeated failures and claiming no lessons were learned from a previous outage in August 2023 that affected over 700,000 passengers. While the fault was fixed within 40 minutes, the cascading effect on such a tightly scheduled system meant recovery was prolonged, with airlines facing millions of pounds in costs for care and assistance, though no cash compensation is payable to passengers as the issue is considered an "extraordinary circumstance" beyond airline control.
The government also expressed concern about the economic and reputational damage. While Nats generally performs well, repeated failures suggest a lack of resilience in its critical national infrastructure. The underlying cause of an earlier, similar disruption on Monday, August 28, 2023, was identified as a flight plan that Nats' systems could not process, highlighting a recurring vulnerability in the system. Passengers were advised to check with their airlines and airports for updates, as continued disruption was expected.
