Air traffic controller blames a millisecond-software glitch for flight cancellations

More than 2,000 flights into and out of the UK were cancelled last week after NATS, the company that runs the National Airspace System, traced the disruption to a millisecond software defect on Sept. 8. In a preliminary report released Friday, NATS said the problem involved the flight data system that allocates codes so controllers can identify flights on radar, contradicting earlier speculation about human error. CEO Martin Rolfe said mitigation steps were put in place while a permanent coding fix is tested and deployed, and he denied the incident was linked to military or civil operators’ actions. The UK Transport Secretary Heidi Alexander ordered a full investigation and an independent CAA review.