A preliminary investigation report released by the British National Air Traffic Management Company on the 18th determined that the root cause of widespread paralysis of many airports in the UK and the cancellation of more than 2,000 inbound and outbound flights last week was a “millisecond” software failure. The Associated Press quoted this report as reporting that the investigation showed that the British air traffic control system had a software failure on September 8. “The entire failure occurred within 1 ms,” rather than a human operation error that many people had speculated at the time. The system is responsible for assigning flight codes to allow air traffic controllers to identify flights on radar.

A preliminary investigation report released by the British National Air Traffic Management Company on the 18th determined that the root cause of widespread paralysis of many airports in the UK and the cancellation of more than 2,000 inbound and outbound flights last week was a “millisecond” software failure. The Associated Press quoted this report as reporting that the investigation showed that the British air traffic control system had a software failure on September 8. “The entire failure occurred within 1 ms,” rather than a human operation error that many people had speculated at the time. The system is responsible for assigning flight codes to allow air traffic controllers to identify flights on radar.