Flights at Heathrow and Gatwick have faced significant delays after a technical fault in National Air Traffic Services equipment disrupted departures at both airports on Monday, in the latest of several separate aviation disruptions to hit London’s major hubs in recent days.
Passengers at two of Britain’s busiest airports faced major delays today after a technical failure in air traffic control equipment disrupted flight departures. National Air Traffic Services (Nats) confirmed engineers were on site investigating the issue, which added to a day of operational disruption at both London Heathrow and Gatwick. A spokesman for Nats said: “We are investigating a technical issue which is causing some disruption to flight departures. Our engineers are on site and we will provide an update as soon as we can. We apologise for the delay this will cause to journeys, passengers should check with their airline on the status of their flight.”
The scale of the disruption
While some reports have suggested flights were entirely grounded, live flight data indicates departures continued at both airports throughout the disruption, meaning the more accurate description is one of major delays to departures rather than a total shutdown. Even so, the impact on passengers has been significant: at Heathrow, some passengers reported aircraft sitting on the ground for between 90 minutes and two hours, with some flights having their engines switched off while awaiting clearance to depart.
Nats has specifically described the fault as affecting air traffic control equipment, rather than being a problem with the runways or terminal buildings at either airport. There is currently no indication that the disruption is the result of a cyberattack; Nats has not attributed the failure to hacking or sabotage, and the technical cause remains under investigation.
Why the knock-on effect could be significant
Because Heathrow and Gatwick are among the busiest airports in the UK, the disruption carries the potential for a considerable knock-on effect. Even once the underlying equipment issue is resolved, aircraft and crews are likely to be left out of position, meaning airlines will need time to work through the resulting backlog of delays.
A history of similar failures
Today’s incident is not the first time Nats systems have caused significant disruption to UK aviation in recent years. The most serious recent precedent came in August 2023, when a failure in the UK’s flight-plan processing system caused widespread cancellations and delays across the country.
A separate Nats technical failure in July 2025 forced the suspension of departures at Heathrow and other UK airports for more than four hours, with Nats eventually restoring operations by switching to a backup system and reducing air traffic to maintain safety. That 2025 failure prompted Ryanair to call for the resignation of Nats chief executive Martin Rolfe, with the airline arguing that lessons from the earlier 2023 outage had not been properly implemented. In response, the UK’s aviation regulator subsequently required Nats to review and strengthen its contingency arrangements for major system outages, a requirement that makes today’s incident particularly notable.
Part of a wider run of disruption
Today’s fault also follows a succession of separate operational problems at London’s major airports in recent days. On 4 September, a Boeing 787 experienced a technical problem during take-off at Gatwick, forcing the runway to close and causing numerous flights to be diverted, with around 20 incoming flights reportedly redirected as a result.
Heathrow suffered a further disruption on 5 September, when a grass fire near one of its runways temporarily forced the closure of the airport’s southern runway. While there is currently no evidence linking these separate incidents to today’s Nats equipment failure, their proximity has meant a difficult run of days for passengers travelling through London’s two busiest airports.
What passengers should do
Passengers have been advised not to rely solely on general airport departure information, and instead to check directly with their airline, since individual flights can carry very different statuses even while the wider airport experiences disruption. At this stage, the most significant unanswered question remains how long the Nats equipment fault will take to resolve; with no restoration time yet provided, the full scale of today’s disruption, including any resulting cancellations or diversions, cannot yet be determined.
