1 SOURDINE–II: SOME ASPECTS OF THE ASSESSMENT OF NOISE ABATEMENT PROCEDURES Ruud den Boer, Collin Beers, Hans Huisman, Mariska Roerdink, Jelmer Scholte, rgboer@nlr.nl, csbeers@nlr.nl , huisman@nlr.nl , mroerdin@nlr.nl , scholte@nlr.nl , National Aerospace Laboratory, Amsterdam, The Netherlands Keywords: ATM, Noise Abatement Procedure (NAP),Environment, Real-Time Simulation, Safety, Human Factors Abstract The Sourdine-II (Study of optimisation procedures for decreasing the impact of noise) project is a 5 th framework RTD project of the European Union focusing on the development and assessment of Noise Abatement Procedures (NAPs). It started November 2001 and will be finished August 2005. Four parts can be distinguished in the study: 1. Procedure definition (approach and departure) 2. Further development of assessment tools 3. Procedure assessment 4. Procedure implementation In this paper, the project organization and applied methodology, as well as the first two topics mentioned above, are discussed very briefly. However, the main emphasis in this paper is on parts of the procedure assessment work. In the Sourdine-II project a selection of approach and departure procedure is assessed with respect to safety, environmental impact (noise and emissions), capacity, Costs/Benefits, and acceptance by end-users (pilots and air-traffic controllers). This paper presents an overview of the initial results of the assessment work, with emphasis on the real-time simulations which were executed to determine the acceptance by end-users. Also, a brief overview of a part of the safety study is presented. The work on the procedures implementation plan has just started and is not included in this paper. Both in the real-time simulations as well as in the safety analysis bottlenecks for the implementation of the concept are identified. These bottlenecks will help the operational concept developers to find improvements for the operation before a successive assessment is done. 1. Introduction With the continuing growth of air-traffic as well as the ever increasing level of urbanisation around most airports, the impact of aircraft noise and emissions on the quality of life for the surrounding communities has become a serious issue to be dealt with. Many airports already face the conflicting problems of increasing their airport capacity to meet the amount of traffic, and the increasing pressure from the general public to reduce environmental impact, particularly noise and emissions, of the increased traffic volume. This has already resulted in specific local constraints to the operation of aircraft, not only around major airports such as Amsterdam (Schiphol), London (Gatwick) and Frankfurt, but also more regional airports are already experiencing the pressure to impose constraints to aircraft movements. Therefore, reduced nuisance to the community is a serious issue for the air-transport industry if the projected sustained growth is to be pursued. Work in three main areas can be identified to improve the situation: 1. Source noise reduction 2. Regulation and land-use planning 3. Noise Abatement Procedures. Many efforts are already being undertaken (and are still continuing) to reduce the source noise itself by the introduction of more silent aircraft and engines. Also, regulations are nowadays applied at many airports in the form of restrictions to older airframe/engines, curfews and noise charges. At the planning of new urban areas it is pursued more and more to avoid areas which will be affected by aircraft noise. A third way of improving the situation is the development and implementation of new approach and departures procedures to provide increased air- transport capacity while maintaining a high level of safety and complying with ever-stricter environmental constraints.