Estimating Cycles to Maintenance Events For Jet Engines Using Engine-specific Measurement Residual

This paper introduces a data-driven method for predicting remaining cycles to major maintenance events in commercial jet engines, developed for the PHM North America 2025 Data Challenge. The method leverages measurement residuals that capture sensor deviations from expected values after accounting for operating conditions with simple linear models. These residuals serve as interpretable indicators of engine health. Health indices are constructed for High Pressure Turbine and High Pressure Compressor visits, while Compressor Water Wash events are estimated through linear extrapolation.