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Approach Noise Trials – ANT

The project has been carried out within the framework of the Centre for Sustainable Aviation at KTH with support from Novair, Swedavia and LFV. The background is the opportunity that have arisen during the pandemic, which meant that regular air traffic for periods decreased by up to 90%. This situation gave rise to a unique availability of both airspace and aircraft, which has been used in the project. The project has carried out controlled approaches at Arlanda (runway 26) where two Novair aircrafts (Airbus A321) were flown with predetermined routes, speeds and configurations (engine, flaps, landing gear).

Figure 1: Satellite photograph over the measurement area at Arlanda. The red line, extending out 17 nm from runway 26, marks the ground track all aircraft followed. The red markers mark long term measurement positions for project ULLA and white markers mark the additional measurement positions for project ANT.
Figure 2: A photograph of the three different setups used during the measurements. The ordinary microphone setup can be seen at the bottom left side, the binaural recording setup can be seen to the right and in the middle the mast microphone is shown.

Sound immission on the ground were then measured within the framework of the CSA project ULLA, which has deployed measuring stations around Arlanda. A total of 18 flights were conducted during week 14 and the sound of an aircraft passage over a microphone was recorded at 31 positions. This data is then converted to 1/3-octave bands in the frequency range 25 Hz-20 kHz. In addition, sounds were recorded binaurally in 5 positions with so-called dummy heads for later use in psychoacoustic tests.

In summary, the measurements and the project were carried out entirely according to the original plan. It can also be mentioned that the project received good media attention with, among other things, an article in “Ny Teknik” and a feature in SR P1 Dagens Eko.

The data collected will primarily be used by five projects run by the Swedish Transport Administration with links to the KTH-Centre for Sustainable Aviation (CSA) namely: ULLA, CIDER, OPNOP, TREVOL and ERAS. After request, data can also be shared with other research or non-commercial projects. 

Technical report for the KTH/Novair project Approach Noise Trails (ANT), spring of 2021 (pdf 681 kB)

 Project members

Mats Åbom
Mats Åbom professor emeritus
aebjo
Karl Bolin
Karl Bolin associate professor
Somayan Basu
Somayan Basu