Effect of time-dependent flight loads on turbofan engine performance deterioration

An analytic evaluation of the dynamic effects of two flight load conditions of the JT9D-7/747 propulsion system is conducted. Predicted performance changes associated with a once-per-flight vertical gust and a typical revenue service landing are calculated. The predicted dynamic load effects on thrust specific fuel consumption are found to be negligible. The results indicate that the quasi-steady state approach to flight loads modeling is adequate to investigate the factors important to the deterioration process.