During the last few decades engineers have been designing wind turbines of increasing size seeking lower values of cost of energy (CoE). A great amount of research has been done recently seeking alleviation of aerodynamic loads on the rotor and support structure and thus reducing material costs and CoE. At the same time, Finite Element Method (FEM) tools have been introduced more and more as part of the design process for structures, drive system and mechanisms of these machines. Coupling FE models with in-house modelling tools is a powerful means to enhance designs despite risking computation trouble. The present work explains a computation method to couple a comprehensive rotor aerodynamic model, including inflow and loads unsteadiness and dynamic stall, to a finite element based Multibody model of a wind turbine.