A Transonic Small Disturbance code originally developed at Canadair for the analysis of 3D wing/body/pylon/store configurations (AGARD CP-412-8) has been extended to calculate flows around complete aircraft such as the Challenger Executive Jet.The program uses a modified Transonic Small Disturbance equation discretized in cartesian and cylindrical coordinates and a grid embedding technique to capture flow details around specific components. The equation is solved using a successive line over-relaxation technique applied in two phases. In the first phase, the flow field is relaxed in the overall crude grid and in the winglet cylindrical grid. In the second phase, the crude grid and the various embedded fine grids are relaxed in alternating steps. The interaction between the various grids is through simple linear interpolation.The program is capable of representing Challenger-type wide body fuselages, large aspect ratio supercritical wings, high by-pass turbofan engines and canted winglets. Correlations with wind tunnel and flight test data demonstrate the capability of the method.