Flight-Configuration-Based Analysis of Emissions and Noise Interdependencies

Artikel i vetenskaplig tidskrift, 2025

A unique series of flyover tests was conducted during the pandemic to study how variations commonly found in standard approach procedures primarily affect the noise level on the ground. The pandemic created unique conditions as the reduced air traffic provided the opportunity to perform these tests and collect noise measurements that are almost clear from background noise. The tests were performed with two A321neo aircraft one morning in April 2021 at Arlanda Airport, Stockholm. This work takes advantage of this database to develop an understanding of the influence of variations in configuration, speed, and altitude on the environmental impact. Interdependencies between noise, CO2, and non-CO2 emissions are closely studied, and the significant findings are presented and discussed. It is shown that, for early configurations, before landing gear deployment, there is a substantial tradeoff between CO2 and non-CO2 emissions, and careful consideration of the latter should be taken to avoid areas of critically low idle power. Noise in these configurations is mainly affected by the impact of the aircraft-microphone distance on the measurements. For the configurations that follow, CO2 emissions become more relevant as the fuel flow increases due to the increase in drag, which also results in an increased noise level that, in these configurations, shows a significant dependency on aircraft speed with an increase of 1 dB for every 10 knots. Based on these findings, some actions are proposed to minimize the impact of each configuration.