-XXX-
When replying, please quote :
Référence à rappeler dans la réponse : EC 9/14.17/55.1 - 0353 11 May 2007
Mr David Delcampe
DG Environment
Unit C3 (Air Quality and Transport)
European Commission
Subject: ECAC Document 29 – Airport Noise Modelling
Your e-mail of 10 May asked for a status report on the subject document. Please therefore find at Appendix 1, a report detailing the development of the document up to and including the latest (3rd) edition, together with current work on the remaining volume. It also mentions the related developments at ICAO level.
I trust that this provides a suitable answer to your request. If you have any further queries, please do not hesitate to call me on (33) 1 4641 8542.
Yours sincerely,
W A HOUSEMAN
Regional Officer - Environment
Appendix
STATUS REPORT
ECAC-CEAC Doc 29 – Aircraft Noise Contour Modelling
Background
1. The original version of ECAC-CEAC ‘Report on Standard Method of Computing Noise Contours around Civil Airports’ (Doc 29) was published in 1986 and was described as the 'best practice' methodology to have been developed up to that time. A revised 2nd Edition was released in 1997 and introduced a number of additional features without changing the fundamental content of the document. This second edition was adopted by the European Commission as the basis of the ‘interim method’ for producing strategic noise maps under the provisions of Directive 2002/49/EC.
2. However, Doc 29 (2nd Edition) was considered to have two major limitations, apart from having been overtaken by actual technology improvements. Firstly, it focused mainly on the algorithms to be programmed into physical computer models and it contained little advice on the practical application of the methodology. Secondly, it provided none of the data that is an essential component of any real modelling system. Thus its practical value diminished with time, such that it became obsolescent for noise modelling specialists and was considered too narrow and theoretical for potential users. The ECAC environment committee therefore established the AIRMOD group in 2001 to develop a new version of the document to overcome these limitations.
3rd Edition
3. The latest 3rd Edition of Doc 29 comprises two volumes. Volume 1 is entirely new and is intended principally for noise model users, i.e. the aviation policymakers and planners who need noise contour maps to inform their decisions, together with the technical practitioners who produce the contours. The aims of Volume 1 are to explain, as non-technically as possible, the principles, applications and limitations of aircraft noise contour modelling, the modelling options and the precautions necessary to ensure that valid results are produced reliably and cost-effectively. Volume 2 is designed principally for those who construct and maintain aircraft noise contour models and is the proposed replacement for the previous 2nd edition of Doc 29. It recommends a specific methodology for calculating aircraft noise exposures around civil aerodromes, including descriptions of suitable algorithms.
4. Overall, this new guidance represents a major advance in three important respects. Firstly, it provides entirely new and detailed guidance on the practical implementation of aircraft noise contour modelling, especially on the importance of correctly representing aircraft types, their operating configurations and procedures. Secondly, it fully describes up-to-date algorithms incorporating the latest agreed advances in segmentation modelling (the recommended methodology). Finally the methodology is supported by an on-line aircraft noise and performance (ANP) database and can be applied to any airport scenario. The approach recommended in Doc 29 (3rd Edition) is considered by AIRMOD and by the international aircraft noise modelling community to represent current best practice for general application, although the need for ongoing review and development is recognised.
5. ECAC Directors General endorsed the publication of the ECAC Document 29 (3rd Edition) in December 2005. They also encouraged the widespread use of this methodology by ECAC States and invited the Commission to align its Environmental Noise Directive with the guidance contained in this latest version. The document is available on the ECAC website in English and French versions.
6. AIRMOD has now commenced work on a further volume to provide guidance on the practical validation of noise contours against actual noise measurements. While this activity may produce some minor changes to the methodology, it is not expected to change the fundamental guidance. One of the main aspects to be tackled in this third volume is the provision of guidance on obtaining good quality noise measurements. Noise measurements obtained around airports will often have as much uncertainty associated with them as the contours generated by a computer model itself. Guidance is therefore required to cover the noise measurements as well as the modelling aspects. It is noted that both SAE and ISO have been developing updated guidance on good practice techniques in airport noise monitoring. It has been agreed that much of this material should be incorporated in the third volume of Doc 29 by reference, rather than reported in detail.
Related Developments in ICAO
7. ICAO’s equivalent guidance to ECAC Document 29 is ICAO Circular 205. This document was published in 1988 and has not been updated since, thus it still accords with the first edition of ECACDocument 29. A draft replacement for ICAO Circular 205 has been developed, based almost entirely on Volume 2 of ECAC Document 29 3rd Edition. This draft replacement was submitted to the CAEP/7 meeting in February 2007 and was unanimously endorsed for publication as an ICAO manual to replace ICAO Circular 205.