Aircraft Approach Noise Trials

This article presents the results from a series of aircraft approach trials that were conducted with the aim to investigate noise reduction procedures within the boundaries of a normal ILS approach. The significant decline in air traffic at Stockholm Arlanda, that occurred during the pandemic meant that the empty airspace and the availability of grounded aircrafts could be utilized to perform controlled flights - something that would have been difficult to achieve during normal traffic conditions. The approach trials were performed by two Airbus A321, which alternately carried out interrupted landing procedures starting 17 nautical miles (nm) from the runway threshold. During the trials, the aircraft speed and configuration (high lift devises and landing gear) were varied according to a predetermined schedule. To capture these variations, flight data (FDR) were recorded while the noise on ground was measured at positions approximately once every nautical mile along the flight track. Results suggest that speed and configuration recommendations can be effective to reduce noise, especially for the final 7 nautical miles of the flight track. However, whether a low speed is to be advocated during the entire approach is currently unclear.