Condition based aero-engine maintenance(CBM) decision based on condition monitoring information is an important issue to the safety operation of airlines.In this paper aero-engine historical data of removal due to performance degradation were analyzed
and a functional relationship between aero-engine performance parameters and time-on-wing was established using Weibull proportional hazards regression model.Furthermore
maintenance decision threshold is determined by the minimum maintenance cost or maximum availability strategy.Thus
an objective quantitative decision method for optimal maintenance decision was provided.Finally
the failure data of CF6 aero-engines were analyzed in detail as an example using the method mentioned above.The result shows that the method has high practical value for aero-engine CBM decision.