The transport secretary Patrick McLoughlin has faced serious questions from a House of Commons Select Committee after the computer error that caused widespread disruption across UK airspace on Friday December 12th.
Over 300 flights were cancelled or delayed, leading to chaotic scenes at British airports.
Mr McLoughlin described the glitch as “simply unacceptable”.
The National Air Traffic Control System (NATS) suffered a similar problem in December 2013, which also grounded flights thanks to a telephone failure in the NATS centre at Swanwick.
However, Mr McLoughlin defended NATS, telling the Transport Select Committee: “The average delay this year in NATS is 2.5 seconds per flight, whereas the rest of Europe we're taking about 30 seconds."
He claimed the incident had caused 16,000 minutes of delays, as opposed to the 126,000 resulting from the previous failure in 2013.
The Civil Aviation Authority has launched an independent inquiry into the incident.