Airbus airframe noise reduction—A European harmonized research effort

Abstract

Very large aircraft—such as the planned Airbus A3XX—require correspondingly high lift forces and extended landing gear structures, thus causing potentially very high airframe noise levels during the landing approach. This problem was realized by the Airbus Consortium, and the first relevant research initiatives date back to the early 1990s. Soon after, initial research at DLR began under contract to Airbus Industrie, dedicated to landing gear airframe noise. Recognizing the general challenge of research for aircraft noise reduction at that time, a European Noise Reduction Initiative (ENRI) was proposed, dealing with both engine and airframe noise. Subsequent technical discussions, however, led to separate programs for engine and airframe noise research, the latter being initiated under the acronym RAIN (reduction of airframe and installation noise). RAIN encompasses analytical and experimental work to describe, predict, and reduce the noise both from landing gears and high lift devices. In parallel, national research programs began: In France wind tunnel and flyover experiments relate to the whole aircraft airframe noise characteristics, while corresponding research in Germany focuses on high lift devices noise. In Great Britain, noise modeling is performed for landing gear noise prediction. These national efforts are coordinated by the Airbus partner companies (3E-program).