// BBC BUSINESS NEWS — FINANZA
Flight chaos caused by 'millisecond' software defect, report says
Thousands of passengers were delayed by the NATS outage
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.
The failure led to more than 2,000 flights being cancelled and hundreds of thousands of passengers affected, with some sleeping on airport floors or getting stuck overseas.
Nats chief executive Martin Rolfe told the BBC he would not resign, saying the software defect was "very, very obscure."
"You can fly to almost anywhere from almost any airport at almost any time. If that stops, even for a moment, then you get huge disruption.
"My job is to make sure that we have this happen as infrequently as possible," he added.
Transport Secretary Heidi Alexander called the disruption "completely unacceptable", while industry body Airlines UK is writing to Nats to demand immediate compensation for costs incurred.
The incident prompted questions over the resilience of Nats' systems, and some airlines questioned the position of Mr Rolfe.
There has also been anger from passengers about how much support they got from airlines, and about the fact that they are unlikely to be entitled to compensation because the regulator judges the situation was extraordinary circumstances.