Flight disruption 'not caused by any incorrect actions' - report

A software defect, not “any incorrect actions,” was behind an air traffic control disruption on September 8 that led to more than 2,000 flight cancellations, according to a preliminary report released by Nats. The issue traced to software that allocates codes to individual aircraft for radar identification; it occurred “in the space of a millisecond.” Flights in and out of the UK were axed, affecting hundreds of thousands of passengers and extending disruption into the next day. Nats said controllers in London Area Control lost access to some live flight data and used manual fallback procedures, reducing the number of aircraft allowed for safety. Transport Secretary Heidi Alexander called the disruption “completely unacceptable” and tasked the CAA with an independent review.