UK Flight Chaos: ‘Millisecond’ Software Error Disrupted Hundreds Of Thousands Of Passengers, Nats Report Says

A previously undetected software defect in the UK's air traffic control system caused widespread disruptions to over 200,000 passengers across the UK and beyond. The failure, reported by National Air Traffic Services (Nats) on September 8, was triggered by a millisecond-level error that corrupted flight data. The glitch began at 10am when engineers noticed the link between the National Airspace System (NAS) and the London area control system was disrupted.

By 10.06am, the system appeared to have recovered without any impact on operations, but investigations continued. The software fault occurred while processing a manual request for an aircraft code, pausing the process for an unspecified higher-priority activity. When the request resumed, the defect caused the software to produce corrupted data, affecting subsequent flight updates.

By 1.32pm, the system had failed completely, forcing controllers to manually handle tasks and airlines to inform passengers of restrictions. The incident lasted until 7.30pm, with over 2,000 flights cancelled and a backlog taking more than two days to clear. Nats CEO Martin Rolfe apologised for the disruption, stating it was unrelated to previous failures and unrelated to any incorrect actions by operators.

The Civil Aviation Authority (CAA) has announced an independent review of the incident and Nats' resilience plans, which will be published within six months. Airlines have demanded compensation and action to prevent a recurrence, with some calling for Nats' chief executive to resign.