Since 22 January 2002, for how many days has height capping been in operation at Swanwick?
When height capping has been used at Swanwick, for how many hours has it been used on each occasion?
For how many days has height capping been in operation at West Drayton over the past three years?
When height capping has been used at West Drayton, for how many hours has it been used on each occasion?
I explained in my earlier letter that we do not collect statistics on the number of flights that are height capped. However I have re-checked the position and what I am able to provide is information which indicates the actual height levels of aircraft operating in the London Flight Information Region, disagreggated between aircraft operating above and below Flight Level 250. This is the dividing line for distinguishing between aircraft flying at low level and those operating in the upper airspace. This information is attached and covers the four years from 1999 to 2002.25
The data does not tell you whether these aircraft were flying at the flight level originally requested by the aircraft operator or at a height capped level. The data does however provide a general indication of whether there has been a material change between flight profiles for the three years from 1999 to 2001, before Swanwick opened, and for 2002, the first year after Swanwick entered operational service. As you will see from the tables, the introduction of Swanwick into operational service has made no discernible difference to the proportions of aircraft flying above and below Flight Level 250. If anything, there has been a slight decline in the number of low level flights. In 1999 (excluding flights outside controlled airspace) there were 1,209,464 air transport movements above Flight Level 250 and 481,385 below this flight level. In 2002, there were 1,285,208 flights above Flight Level 250 and 486,617 below this level. In other words, the ratio between high level and low level flights has hardly changed from 72% and 28% in 1999 to 73% and 27% in 2002.
It is not possible to provide the information requested in this latest set of questions about the hours and days when height capping has been in operation, because the information is neither collected nor retained, there being no operational or business reason for compiling such statistics.
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25 Not printed.