BBC News
Katy Austin, Tom Espiner, and Simon Browning
18 September 2026
An air traffic control failure that sparked widespread travel chaos earlier this month was caused by a "software defect" affecting the system underpinning UK air space management, the national air traffic service Nats has said.
The problem happened "in the space of a millisecond", Nats said, leading to the system producing corrupted data.
In an initial report, external, Nats said the software defect meant air traffic controllers had reduced information available, so restrictions were put in place to limit air traffic to maintain safety.
The defect occurred at 10:00am on 8 September, but it did not become apparent this was a serious problem for another two and a half hours.
The system restart did not start until just after 3:15pm, and restrictions on UK airspace were not lifted until 7:30pm...
