The WHeSI project originates from a collaboration between ZHAW and the Swiss manufacturer Kopter. It aims to develop a high-fidelity simulation model to support the design and certification of Kopter’s AW09 - a new-generation, single-turbine helicopter that aims to revolutionize the light helicopter market and is the first entirely clean-sheet design in its class since the last four decades. The goal of the project will be achieved through an innovative system identification method, which consists in the time-domain identification of a fully physics-based, non-linear helicopter model. The systematic application of this so-called “white-box” approach in the rotorcraft industry is unprecedented. Compared to more traditional techniques, this method will improve the quality and accuracy of the identified model, in particular its ability to predict never tested flight conditions, which is critical for several applications (such as, among others, analysis of flight mechanics and handling qualities, advanced Automatic Flight Control System design, envelope expansion, failure conditions analysis)