Recent development in turbofan engines has led to the integration of planetary gear boxes. The application of a planetary gear box in an aviation environment places high demands on structural and dynamic system behavior. The ring gear mount is the component that connects the gearbox to the surrounding engine architecture and impacts both. The aim is to increase an identified critical Eigen frequency of the gear box system, while the ring gear mount must comply with flexibility, mass and buckling constraints. In this paper a CAD geometry-based optimization process in conjunction with a reduced gear box model is presented. The ring gear mounts shape is optimized via three different parametrization strategies and the use of single-and multi-objective evolutionary-based algorithms. The optimization resulted in a 30 percent increase of the systems critical Eigen frequency and a 5 percent reduction in component mass. The optimization approach and parametrization strategies are versatile and can be transferred to different optimization problems. NOMENCLATURE buckling Eigen value distance to design space limit natural frequency , running variable along a spline structural stiffness non-variable distance component mass design parameter radius Sagitta wall thickness , Cartesian coordinates