A novel model approach to characterize the changes in longitudinal and lateral aircraft dynamics due to local icing is analytically derived. This model extension is formulated as a separate module in the aircraft flight mechanics simulation and can be used in existing simulation models. Using the example of the former DLR research aircraft VFW614 ATTAS, the base information about the aircrafts iced aerodynamics is obtained by 3D CFD calculations with numerically generated ice shapes. With the resulting data model parameters describing a local aerodynamic degradation are estimated. Simulation of the local ice influences on the dynamic aircraft behavior show the models capabilities to cover aerodynamic changes during a deicing process.