To ask the Secretary of State for Transport what percentage of maximum airspace capacity over London and the South East is currently used; and what contingency plans he has to (a) ration and (b) otherwise allocate airspace if demand should exceed supply. (261887)

[holding answer 9 March 2009]: Although airspace has a finite volume, available airspace capacity is not a constant—it varies according to the declared capacity of air traffic control units and airspace sectors as a function of time.

The central flow management unit (CFMU) at Eurocontrol, the European organisation for the safety of air navigation:

http://www.cfmu.eurocontrol.int/cfmu/public/subsitehomepage/homepage.html

provides an air traffic flow and capacity management service on behalf of air traffic services and airport operators across Europe before traffic is handled operationally by air traffic control. The CFMU has access to a database containing flight plan information on every aircraft that is planning to fly in European airspace and uses this information to meet its objectives of balancing demand and capacity, keeping delays to a minimum and avoiding congestion, bottlenecks and overload.

Consequently, airspace capacity management in the UK is an operational matter for the air traffic control provider, NATS. The following link to the NATS website provides an overview on traffic volumes handled by NATS from their various centres and flights handled at major UK airports:

http://www.nats.co.uk/text/47/operational and safety.html