(2) what estimate his Department has made of the proportion of aircraft using the continuous descent approach at (a) Heathrow and (b) all designated UK airports in each of the last four years;
(3) what assessment his Department has made of the use of the continuous descent approach (CDA) at (a) Heathrow and (b) all designated UK airports, with particular reference to (i) the distance from the airport at which CDA begins and (ii) the altitude at which CDA begins.
Aircraft landing at Heathrow have been required for a number of years, wherever practicable, to operate a continuous descent approach (CDA).
This is in line with the Government's policy of encouraging, together with the Civil Aviation Authority (CAA) and NATS, the use of CDA, where airspace and safety considerations allow. The procedure seeks to reduce the noise of arriving aircraft by ensuring that aircraft remain as high as possible for as long as possible and that segments of level flight during descent, which increase engine noise, are avoided. Guidance in the form of an arrivals code of practice on the use of CDA, developed in partnership with the industry, was originally issued in February 2002. This guidance has been kept under review and a revised code was published in November 2006. The code can be accessed on the departmental website at:
The original focus of the arrivals code was to promote CDA at the three London designated airports (Heathrow, Gatwick and Stansted). Following the successful implementation of the code at these airports, the code has been used by NATS as a basis to promote and encourage greater use of CDA at other airports nationally and internationally. However it has to be acknowledged that local operational circumstances and restraints can vary from airport to airport. CDAs are agreed by air traffic controllers and pilots on a flight-by-flight basis, according to weather and traffic conditions. In all cases, NATS' overriding consideration is the safe and efficient operation of air traffic control (ATC) operations.
CDA performance and developments are monitored. Reports are regularly presented for review by the consultative and technical sub-committees at the three London designated airports Heathrow, Gatwick and Stansted. Current CDA performance consistently averages 80 per cent. throughout the 24-hour period of operation.