On the use of noise annoyance as a design optimization constraint: The COSMA experience

Aircraft noise is nowadays one of the most urgent concerns in the development of the air transportation system. The tremendous grow rate of the number of passengers during the last two decades has generated a significant increase of the number of airports, with a commercial rebirth of secondary air terminal. As a consequence, the number of people affected every day by the noise produced by aircraft operations has sensibly increased. Within this framework, the effort of the research community during the last 20 years has concentrated, according to the regulation, on the abatement of the noise level. Lately, the possibility to include in this process considerations related to the annoyance produced by the exposition to aviation noise has received a major improvement. Such an approach would allow the designer to explore unconventional possibilities, widening the horizon of the future technological scenarios and multiplying the options available to reduce the impact of the community noise on the population. One of the major difficulties in the integration of perception-based considerations resides in the not easy translation of psychoacoustic indicators in terms of design variables. The present papers describes the approaches developed during the EU-funded research projects SEFA (Sound Engineering for Aircraft, FP6/2004-2007) and its follow-up COSMA (Community Oriented Solutions to Minimize aircraft noise Annoyance, FP7/2009 on). The problem is here approached from the point of view of a research engineer in aeronautical sciences. Specifically, the mechanism identified to drive the optimization process to weakly annoying configuration is described. Special attention is payed to the description of the relevance of annoyance related objectives in the resulting workflow, and how these objectives are capable to drive the designers' choices.