Air Traffic Control Issue Disrupts Flights at Heathrow, Gatwick and Other UK Airports

A technical fault in the flight processing system used by National Air Traffic Services (NATS) disrupted flights at several major UK airports on Tuesday, September 8, including London Heathrow and Gatwick, causing widespread delays and grounded departures.

According to reports, all departures were temporarily stopped at London Heathrow after the issue emerged. Gatwick, Manchester, Stansted, and Birmingham were also significantly affected, with additional reports of disruption at Edinburgh, Luton, Aberdeen, and Glasgow. Ireland's Dublin Airport reported knock-on delays to flights arriving from and departing to the UK as well.

What Went Wrong

NATS, which manages UK airspace, traced the fault to its flight processing system, the software responsible for handling departing aircraft's flight plans. In an update issued at 3:25 PM, NATS said: “We have identified that the issue was in our flight processing system. Our engineers are on site and working urgently to resume normal operations as quickly as possible.”

By 4:40 PM, NATS reported progress: "We have implemented a fix and our flight system is starting to recover. We are continuing to work closely with our airline and airport customers on recovery." The company apologized "sincerely for the disruption to people's journeys today" and asked passengers to continue checking with their airlines.

Airspace itself remained open throughout the incident; the fault primarily affected NATS's ability to automatically process outbound flight plans, requiring restrictions on the flow of departing aircraft while engineers worked on a fix.

Scale of the Disruption

The numbers illustrate how widely the fault was felt: about 281 of Gatwick's roughly 850 scheduled flights were delayed, nearly a third of its total operations. Manchester saw 249 of 650 flights delayed, and Birmingham saw 101 of 300 flights delayed. Some flights already airborne were reportedly held in holding patterns before being cleared to land.

Transport Secretary Heidi Alexander acknowledged the disruption publicly. "I'm aware of a technical issue impacting flights at airports including Heathrow and Gatwick," she wrote. "Technicians have identified the issue and are fixing it as we speak. I know this will be frustrating for passengers and I'm sorry. Please check with your airline for latest advice."

Airlines Respond

EasyJet, a major operator at Gatwick, confirmed some of its flights were unable to operate as a result of the failure. "A Nats Air Traffic Control system failure this afternoon is unfortunately causing delays to flights across Europe with some flights unable to operate," the airline said, adding that it would provide affected customers with a free transfer or refund, along with meals and hotel accommodation for those who need them.

British Airways, which has its main hub at Heathrow, said the disruption was "entirely out of our control" and that its teams were working to get customers "on their way as quickly as possible."

What Passengers Should Know

If you are traveling today, check directly with your airline before heading to the airport. Airlines typically send updates by text or email when flights are delayed or canceled, and flight status can also be monitored through an airline's website or app. Heathrow and Gatwick are both advising passengers to check their individual flight status and only travel to the airport once a flight is confirmed.

Background on Recent Disruptions

This is not the first time NATS's systems have caused major disruption. A significant outage in August 2023, triggered when an unusual flight plan caused the primary and backup processing systems to enter fail-safe mode, led to more than 1,600 canceled flights and affected over 700,000 passengers, ultimately costing airlines more than £100 million in refunds and compensation. A separate, radar-related technical problem also disrupted flights at Heathrow and other major UK airports for several hours in July 2025.

NATS has said it invested in upgrades and additional safeguards following the 2023 incident. Tuesday's failure is likely to renew questions about the resilience of the UK's air traffic control infrastructure, particularly heading into busy autumn travel periods.

What Happens Next

Even with a fix deployed, disruption is expected to continue for several hours as airlines work to reposition aircraft and crews that were left out of position during the outage. Passengers scheduled to fly later Tuesday or on Wednesday may see knock-on delays as a result.

Aviation officials are likely to review what caused the fault and how quickly it was addressed. For now, travelers are being urged to stay in contact with their airlines and remain patient as staff work through the backlog.