The Canadian Department of National Defence has identified a need for improved engine health monitoring procedures for the new Canadian Patrol Frigate (CPF). The CPR propulsion system includes two General Electric LM2500 gas turbines with multi-stage, variable-geometry axial compressors. A general method for predicting the thermodynamic performance of these compressors has been developed. The new technique is based on a meanline state-stacking analysis and relies only on the limited performance data typically made available by engine manufacturers. The method has been applied to the LM2500-30 marine gas turbine, and variations in engine performance that can result from a malfunction of the variable geometry system in service have been estimated.