Multiobjective optimisation of flight paths for noise level mitigation and sound quality improvement

The present work deals with the multiobjective, multidisciplinary optimisation of takeoff and approach operations of a commercial aircraft aimed at the mitigation of the impact of aviation noise on the population. The innovative approach used here couples the minimisation of the aircraft noise level at the certification points with the improvement of the sound quality. The latter objective represents the main novelty of the present work and is addressed using a spectral-matching approach to make the aircraft noise as close as possible to a target sound. The rationale underlying the research is the development of a community-oriented approach to the assessment airport operations in view of the complete redefinition of the future airport scenarios. Indeed, the air traffic growth, the rapid expansion of urban areas around airports, and the expected advent of urban air mobility, are transforming the aviation noise into a serious hazard to the sustainable development of society. The sound-quality-based objective imposes a comprehensive multidisciplinary approach also in the procedural optimisation, due to the detail required to estimate the noise spectrum composition. Two merit factors are minimised, specifically the EPNL at the noise certification points and the Lp-norm of the difference between the noise produced by the configuration under analysis and a target sound. The target sounds are obtained by using sound engineering techniques aimed at the sound quality improvement, on the basis of the results of the psychometric tests campaigns performed within the projects SEFA and COSMA. The minimisation is achieved adopting a global evolution method, and the results are presented in terms of approximated Pareto frontiers for a single-aisle aircraft in both takeoff and landing conditions.