Noisy airplanes no more
Noisy airplanes no more lead image
A new runway at the Stockholm Arlanda Airport caused rumblings in the community. The increased noise triggered vocalized discontent from the airport’s neighbors. Their complaints were justified: noise disturbances trigger stress reactions in the body, which can lead to medical issues like declining mental health and cardiovascular disease.
However, loud aircraft are not disappearing anytime soon. To find an alternative solution, Johansson and Bolin investigated causes of the loud descent of a common passenger airplane to provide noise-reducing recommendations.
“The WHO estimates at least one million healthy years of life are lost yearly from traffic-related environmental noise in Western Europe, corresponding to almost one day of good health loss per year for every European citizen,” said author Anders Johansson. “The bulk of this health cost can be attributed to sleep disturbance and annoyance.”
To determine the factors contributing to the noise of the Airbus A321neo, the authors placed microphones on the ground at various locations and cross-referenced the recordings with information about the flights, like speed, altitude, engine thrust, configuration of high-lift devices, and weather.
Aircraft speed and configuration were found to be the two most significant factors determining the sound level during its descent, accounting for 70% of the variation.
Most potential improvements are long term and involve redesigns of the planes. However, the authors did identify one immediate solution to make descents significantly quieter.
“To minimize noise during the final approach, it is advisable to delay the deployment of the landing gear for as long as feasible, as this component has been identified as the primary contributor to the overall increase in sound levels,” said Johansson.
Source: “Analysis of landing noise from Airbus A321neo using long term noise measurements and flight recorder data,” by Anders Johansson and Karl Bolin, Journal of the Acoustical Society of America (2023). The article can be accessed at https://doi.org/10.1121/10.0019713 .
