1. A method of predicting flutter comprising the steps of: providing a non-transitory computer readable medium containing instructions stored therein for causing a computer to perform the following steps; determining a set of structural mode shapes; defining a set of principal shapes of modes based on the set of structural mode shapes, wherein the set of principal shapes is smaller than the set of structural mode shapes and wherein said principal shapes of modes is determined using singular value decomposition; determining an aerodynamic damping distribution for the set of structural mode shapes based upon the set of principal shapes of modes; and predicting flutter based on the aerodynamic damping distribution.