FocusUltra High Bypass-Ratio Engine (UHBR)Flutter assessment is on the stability assessment of an aircraft equipped with the currently introduced high-efficiency engines with ultra-high bypass ratios (UHBR) and to compare the critical flutter onset to the same aircraft using standard engines with a smaller fan diameter. The D150 configuration modelled in-house by DLR was chosen, since it is similar to the Airbus A320 in terms of size and dynamic behavior. The setup of the aeroelastic model is shown and results from the flutter assessment clarify differences between the investigated standard and UHBR engine types with respect to flutter onset. Here, the sensitivity study includes varying locations of the UHBR engine in front of the D150 wing and is based on unsteady aerodynamic forces using the doublet lattice method (DLM). In addition, a methodology for the use of CFD based aerodynamic forces is developed and applied to the AMP wing model which allows the comparison to measured flutter data. The aeroelastic models are analyzed with the commercial ZAERO aeroelastic software package.