Next generation aircraft - A challenge for Interior Acoustics Developments

Beside several comfort factors and economic value improvement the aircraft interior noise is of high interest and appears as a differentiating factor of attractiveness for airliners. Since the past decades the focus on noise metrics was set on quantified levels such as A-weighted sound pressure level and speech interference level, today consideration of the pleasantness of interior noise becomes essential to achieve an optimal acoustic design. In parallel there is a strong technology evolution of the propulsion systems, the structure, system and the interior trim designs, which raise new challenges. Several studies have been conducted to understand the perception of aircraft interior noise characteristics and significant difference in the perception has been obtained with no impact on conventional metrics. Accordingly it is essential to understand the excitation, its coupling into the fuselage and the transmission in detail in order to derive efficient noise control measures. To come to this deep understanding only by flight test is impractical therefore it is necessary to reproduce the inflight situation in the laboratory under controlled conditions.