COSMA

Community Oriented Solutions to Minimise aircraft noise Annoyance

COSMA aims to:

• Improve the understanding of the effects of aircraft noise in the airport community
• Develop techniques for modelling the impact of aircraft noise around airports
• Develop engineering guidelines and methods implementing suitable design and operating   practices aimed at minimising community aircraft noise annoyance, supported by a set of validated tools

The first two objectives are intermediate objectives, as they provide the required knowledge and capabilities towards the ultimate goal, i.e., the design of aircraft and its operations for a minimum of annoyance in the surrounding airport community.

Until now, aircraft noise engineering has generally focussed on achieving lower noise levels for individual events and at distances which are relatively close to the runway. The achievements are normally measured and presented in the standard effective perceived noise levels (EPNL) unit, which is also the noise certification unit used internationally.

To achieve innovative and complementary ways aimed at minimising the impact of aircraft noise on airport communities, a number of successive questions relating to functional and chronic (long-term) annoyance have to be addressed:

• What is annoying in a single aircraft noise event, considering typical aircraft noise signatures (spectral characteristics)?
• What characteristics should a Community Friendly Aircraft then have?
• What is annoying in a series of aircraft noise events, considering aircraft signatures and frequency of events?
• What characteristics should Community Friendly Operations then have?
• What are the additional chronic annoyance factors to be considered in a community context?

SEFA (02/2004 – 06/2007) was the first and so far unique approach to applying sound engineering practices to aircraft external noise, i.e., to reducing noise (annoyance) not just by lowering levels, but also by improving the characteristics of aircraft noise signatures.  Addressing the first two questions above, related to analysis of single events, it was a breakthrough in its innovative concept and performance.

In addressing the remaining questions within innovative field and laboratory annoyance studies, COSMA will continue the successful collaboration amongst aircraft noise engineers, sound designers and the noise effects experts. It provides the best possible paradigm for ensuring that the work on noise effects is clearly targeted at improving aircraft design and operations, and, therefore is already taking into account the ultimate goal described above.