Aircraft Design Optimization for Lowering Community Noise Exposure Based on Annoyance Metrics

Abstract

This paper focuses on the annoyance aspect of aircraft noise, which relates to the quality of the sound reaching communities, and attempts to potentially lower this annoyance by optimizing an aircraft’s design. Use is made of sound-quality metrics because these are known to have a high correlation with perceived aircraft noise annoyance. A representative short-range aircraft is optimized for minimal community noise impact by varying the thrust-to-weight ratio and wing-loading parameters. The changes in noise impact are investigated for both certification and sound-quality metrics to quantify design sensitivities. The optimized aircraft is seen to have a noticeably different sound, depending on the metric it was optimized for. The use of sound-quality metrics is seen to provide much clearer information regarding the character of the sound reaching the residents than the conventional A-weighted level and effective perceived noise level metrics used for certification. The certification metrics prove deficient in capturing important aircraft noise characteristics such as its tonal content, which is a strong contributor to the perceived annoyance. Feedback from psychoacoustic tests is required to confirm whether the presented modified aircraft sounds, optimized for the different metrics, are indeed perceived as less annoying and more acceptable.