More and more attention is being devoted to assessing severity of the engine operation for a high number of flights in a minimum of time. Compressor erosion is one of the physical phenomena contributing to this severity. Hence, an effective method is developed which allows a general judgment of the severity of engine operation with regard to compressor erosion. The shortening of the camber line at blade leading edge is selected as the parameter describing the degree of severity. The particle impingement conditions experienced by compressor blades throughout a flight mission are computed using a flight mission simulation and a non-dimensional engine model. Local flow conditions of all compressor blade rows are derived from mean line computations. A dimensional analysis of a straight through swirling annulus flow led to a simplified model of particle separation within the compressor blade rows. It turns out that bypass ratio, bleed setting, and degree of particle separation changing from operating point to operating point are significant drivers of erosion. Fan root and booster suffer less from compressor erosion than the high pressure compressor. The flight segments taxi, take-off, take-off climb, climb, and cruise are significantly impacting the severity of a flight mission with regard to compressor erosion.