Working Group on eVTOL Noise Assessment

Acceptance of close-proximity eVTOL aircraft depends on public perception that they are quiet in relation to the environment. When they are audible, their influence on community soundscapes must not be intrusive. To solve for that, measurement of "quiet" is needed using a physiological model of hearing rather than a sound pressure measurement intended for entirely different applications. While we are starting with baseline noise metrics using earlier methods, we propose a cooperative effort to coordinate development, testing and education about techniques that correlate better with perception of quiet. Two major differences are proposed between current practice and future methods: measure vehicle loudness rather than sound pressure, and measure operations with respect to ambient rather than to meet an arbitrary level for a given land use. These are not new concepts, but require computational resources that until recently were too expensive to be practical.