§ Mr. Jenkin
To ask the Secretary of State for the Environment, Transport and the Regions when the 403W software that failed at West Drayton Air Traffic Control Centre on 17 June was installed; and if he will make a statement. 
§ Mr. Hill
The software which failed on 17 June was a Flight Data Processing System known as the National Airspace System (NAS). The current software version was introduced in January 2000, with an interim upgrade in April 2000. In addition to this, the system's database and configuration parameters are modified each month. Until June this year, this software version had continued the excellent track record of reliability established by the NAS system in recent years.
The failure was cleared by reverting to a previous version of the software and as an additional precautionary measure a system message was input which actively prevented the system from exercising the faulty code sequence. Subsequently a permanent software design solution was devised, tested, and successfully installed. This has enabled National Air Traffic Services Ltd. (NATS) to restore capacity levels in the key Scottish sectors which carry a substantial amount of North Atlantic traffic.