Cost-effective aero-engine washing strategies using Bayesian decision analysis

Purpose This study examined the impact of engine washing on the performance and material degradation of T700 engines, prompted by recent cases of compressor blade failure due to pitting corrosion in S-70 aircraft. Based on the analysis of these incidents and previous research on material deterioration, engine washing can help sustain higher engine performance but may also accelerate metal corrosion. Therefore, the effects of engine washing must be thoroughly evaluated, and an optimal strategy should be established to maintain engine performance while minimizing the risk of corrosion. Design/methodology/approach This study analyzed turbine gas temperature (TGT) margin data from Sikorsky S-70 aircraft using a linear mixed model to statistically assess performance improvement from engine washing. In addition, by reviewing previous research, we analyzed the corrosive effects of washing on engine materials. Furthermore, a Bayesian decision model and fault tree analysis were applied to evaluate the economic feasibility of engine washing. Finally, the optimal engine washing interval was derived by considering both the risk cost and the washing cost. Findings Statistical analysis yielded a p-value of less than 0.05 (p < 0.05), thereby rejecting the null hypothesis that no significant difference exists in the mean TGT margin before and after engine washing. Furthermore, the Bayesian analysis results indicate that engine washing is economically advantageous. Finally, the analysis identified an optimal washing interval of 190 h. Research limitations/implications Future research should incorporate real-time operational data on TGT margin and mean time to failure to improve analytical accuracy. Moreover, further investigation is required to determine the extent to which engine washing contributes to the extension of component life cycles and the reduction of fuel consumption, thereby supporting the development of more practical and cost-effective engine maintenance strategies. Practical implications This study emphasizes the importance of balancing performance improvements with the risks of material corrosion. Furthermore, it provides operators with statistical test results and practical criteria to support decision-making and establish an engine maintenance strategy. Originality/value In contrast to previous studies, this study comprehensively evaluates the impact of aircraft engine washing on TGT margin, considering both performance and material aspects. It uses actual operational data and incident cases to strengthen reliability and practical relevance.