Effect of Aero-Engine Washing on Turbine Gas Temperature Margin

This study investigates the effects of engine washing on T700 engine performance and material deterioration. To assess performance improvement, turbine gas temperature margin data from six Sikorsky S-70 aircraft were analyzed using linear mixed model. The statistical test yielded a p-value below 0.05, rejecting the null hypothesis that there is no significant difference in the mean turbine gas temperature margin before and after engine washing. Regarding material impact, alternate immersion and potentiodynamic test indicated that residual chloride and sulfate ions in the washing water can increase corrosion risk. Additionally, exposure experiments confirmed that the wetting of metals post-washing could also trigger corrosion. Considering these conflicting effects, a Bayesian decision model was applied to determine the economic feasibility of engine washing strategies. The results indicate that engine washing is economically advantageous. Furthermore, considering both risk cost and washing cost, the analysis suggests that an optimal washing interval is 190 hours. The results of this study are expected to contribute to establishing an optimal engine corrosion management plan.