§ Dr. Tonge
To ask the Secretary of State for the Environment, Transport and the Regions (1) what factors were taken into account when final descent paths for aircraft approaching Heathrow were altered in 1995; 
(2) what plans he has to alter the final descent paths for aircraft approaching Heathrow. 
Mr. Robert Ainsworth
The final approach tracks followed by aircraft approaching Heathrow to land have to be aligned with the runways in order to comply with long established internationally agreed standards. They have not changed and cannot be changed unilaterally.
The paths that aircraft follow before aligning with the runway are not fixed, in order to allow for safe tactical integration of up to four streams of traffic, but the area of airspace used for this purpose has been established in its present form for about 30 years. An "early morning landings trial" commenced in September 1995, which required aircraft during westerly operations at night (before 6.00am) to join the 3° glideslope of the instrument landing system (ILS) at or above 3,000 ft (instead of 2,500 ft) and to join the final approach track at not less than 10 nautical miles (18½km) from touchdown. The trial was evaluated and a summary of the findings was published in the November 1998 consultation paper on night restrictions at Heathrow, Gatwick and Stansted airports (copies of which were placed in the Libraries of the House). It was found that the trial procedure produced a reduction in noise exposure in the area between 16½ km and 31½ km from touchdown. Some noise increases were caused in parts of Clapham, Deptford, Lewisham and Blackheath because more aircraft joined the ILS final approach track further from touchdown. A redistribution of traffic over built-up areas can result in gains and losses but may be justified, as in this case, where the gains substantially outweigh the losses. The study also found a small increase in the achievement of the noise reducing continuous descent approach (CDA) procedure even though the CDA instructions were not changed for the trial.639W
Mr. Robert Ainsworth
My Department publishes annual daytime noise contours for Heathrow, Gatwick and Stansted airports. These contours cover the 16 hour day from 0700 to 2300 BST, averaged for the relatively busy period 16 June to 15 September. The contours for 2000 are about to be published by the CAA on the Department's behalf; and the explanatory booklets, including small-scale versions of the contours, will be placed on the DETR website shortly. All take-offs are monitored for compliance with the departure noise limits. The new daytime and night-time limits announced by my hon. Friend on 18 December 2000,Official Report, columns 11–12W, have come into effect. Readings from these and other noise monitors (covering both arrivals and departures) are used, along with radar data on the dispersion of aircraft tracks, to validate the model used to generate the contours. Other measurements are taken, and contours produced from time to time for various studies on behalf of the Department and of the airports.
We do not routinely publish contours for aircraft noise at night at these airports, as research has suggested that, because of the uneven and distinct patterns of operation, these would not be sufficiently well correlated with sleep disturbance and annoyance. However, operations at night are subject to the restrictions, including movement limits and noise quotas made, after consultation, by Notice under s.78 of the Civil Aviation Act 1982; and are monitored and reported by the airports accordingly.
Elsewhere in the South East, noise measurement and contouring are the responsibility of the individual airports. However, noise measurements collated from other airports will help inform the current South East and East Regional Airports Study (SERAS).