Noise from aircraft has long been a nuisance to the residents around Arlanda. A new research project will provide better knowledge about aircraft noise, something that can be used to create quieter routes. The opportunity to start the project has arisen through reduced traffic as a result of the corona pandemic.
“Now that there is both time and space in the airspace over Arlanda due to covid-19, it gives a completely unique situation. In the past, when there were many aircraft in the air at the same time, it was difficult to get good data. This is because qualitative noise data requires that we measure the sound from individual planes at a time,” says Mats Åbom, professor of technical acoustics at KTH (Royal Institute of Technology) and deputy director of the Centre for Sustainable Aviation (CSA) at the university.
The noise measurements will take place with the help of approximately thirty measuring stations set up around Arlanda. These measuring stations have been designed by KTH doctoral student Anders Johansson. Data from the stations must be paired with information about the aircraft’s configuration in the air, such as flapping and engine start-up, data that researchers do not normally have access to.
“With the help of the airline Novair, we get access to the aircraft’s black box and can see how the wing flaps stand, when the landing gear is folded out and such. That is, things that protrude from the plane and that affect how much it sounds. It is a piece of the puzzle we previously lacked, and it is an uncertainty in today’s models for aircraft noise.”
At the start, you want to get up as soon as possible, and off. The landings are worst in terms of noise because approaches take time and take place at lower altitudes for a longer period of time.
KTH researchers will also take a closer look at the psychoacoustic aspects of noise. That is, how people experience and are affected by sound.
“What is it that bothers people? What reactions occur, what causes stress surges? It can be quite subtle sounds that affect and disturb concentration and rest.”
Are there already any hypotheses about changes in flight routes that have been studied at KTH and the research centre?
“One thing we have studied is the so-called “steeper” approach. In other words, to fly in at a higher angle, so that the plane at a certain distance is at a higher altitude, which gives lower noise on the ground.”
Mats Åbom adds that the collected data will be used in as many as five projects linked to CSA that study how noise and other emissions can be minimised.