The project objective is to evaluate the UHBR engine with respect to cabin noise in comparison with a conventional engine. In order to analyze sound propagation through the fuselage, the joint between fuselage skin and cabin lining is experimentally assessed and numerically simulated by a finite element model. The pressure fluctuations on the fuselage surface due to sound radiation from an ultra-high-bypass-ratio engine are simulated and serve as input data to model sound transmission through the fuselage. Model parameters of thermoplastic functional layers are attained by experiments.