The Flexible Combined Imager (FCI) is an instrument on the future geostationary meteorological satellite Meteosat Third Generation (MTG). This communication presents preliminary results on its capability in measuring and characterizing the optical properties of the aerosols, their load, and nature. A numerical simulator has been built that includes top-of-atmosphere scene simulation obtained by a radiative transfer model in the clear atmosphere, and the transfer function of the FCI (spectral response, SNR…) to provide simulated outputs of the instrument. Changes of inputs depicting the atmosphere and the ground yield a series of FCI outputs that are analyzed by means of global sensitivity analysis to assess the sensitivity of FCI to changing aerosol properties.