The availability of a numerical tool capable to predict the vibration level inside the cabin due to main rotor-fuselage interaction is of great importance in helicopter design. Indeed, it would be a source of information concerning the fatigue-life of the structure, that in turn would allow a rough estimate of consequent maintenance costs. Furthermore, such a tool would be helpful also in the process of identifying design solutions aimed to the interior noise reduction, that is a crucial aspect for the widely-requested passenger comfort enhancement. In this paper, the simulation tool is obtained as a finite element structural dynamic model of the helicopter fuselage forced by vibratory hub loads, that are predicted through the aeroelastic analysis of the main rotor treated as isolated. In particular, the emphasis is on the evaluation of the incremental vibration level induced by rotor asymmetry and gust encounter, that could give raise to interior acoustic patterns annoying for passengers and to vibration peaks dangerous in terms of structural fatigue. All the results are obtained for two different flight conditions
