CFD-Icing (CFD-I) is a powerful companion to CFD-Aero (CFD-A) in the design and certification of new aircraft, rotorcraft and jet engines. It can drastically reduce the number of tunnel and flight tests, and their associated costs, by simulating on computers the full Appendix C and beyond such as is proposed in new Appendices D and O. It can also predict performance and moment coefficients in roll, pitch and yaw. These predictions can then be used in original certification or supplemental certifications to the type design, allowing mitigating potential hazards of flight-testing. This work presents an example of the application of FENSAP-ICE to predict 45 minutes of ice accretion on a RC-26B aircraft fuselage retrofitted by the addition of a FLIR sensor and a SATCOM antenna. The predicted aerodynamic penalties are compared with recorded flight test data obtained with simulated ice shapes. Of further interest is that two similar FLIR installations were tested with post-processed data to account for minor differences in the vertical dimension of the FLIR sensor installation. This validation campaign shows the ability of such second-generation CFD-I tools to properly model the impact of ice accretion, starting from clean aerodynamics, to water impingement, to ice accretion, to aerodynamic characteristics of contaminated aircraft.