Overview of aircraft en-route noise prediction.

Community noise near airports is a major aviation noise concern, prompting the development of various modeling tools to predict the noise changes due to airport expansion and fleet changes. Once aircraft leave the terminal area and reach high altitudes, the aircraft noise received on the ground is assumed to be insignificant relative to urban ambient noise and is often neglected. However, this might not be the case, under either of the following conditions: (1) when aircraft fly over areas with very low ambient noise levels, such as in wildness areas, or (2) when an aircraft is powered by advanced propulsion systems that produces high noise levels. There is an increasing need to address both of these issues. Over the past 2 decades, some limited noise modeling capabilities and related research have begun to quantify the high-altitude aircraft noise or “en-route” noise. The purpose of this paper is to review and summarize related noise prediction research conducted through direct technical exchange with researchers, some simple data analysis as well as through a literature review. The authors will draw on experience in developing current aircraft community noise tools and formulate key future research questions and options.