The report presents an initial assessment of the predictive capabilities of computational aerodynamics codes used in industry and academia for predicting the aerodynamic performance impairment of wind turbine blades caused by erosion. Both high-fidelity codes, i.e. Navier-Stokes computational fluid dynamics codes, and lower-fidelity methods, i.e. potential flow codes coupled to integral boundary layer equation and transition model and augmented with empirical correlations, are considered in the exercise. The test cases used for the study consist of wind tunnel aerodynamic experiments carried out in state-of-the-art European and American wind tunnels. The results of this investigation are relevant to predicting the turbine power and energy yield loss caused by erosion.