Design and Service Experience of Engine Life Usage Monitoring Systems

The Planning of a monitoring system should be embedded in an overall concept which considers beside technical and logistic aspects the principles of the aircraft and engine maintenance concept. The split of the entire system into on-board equipment and local or central ground stations should be agreed in an early design phase. All kinds of changes (engine modifications, variation in operating conditions and mission profiles, software updates and processor hardware development) which are likely to become necessary over a period in service of more than 30 years should be envisaged. Adequate means for configuration control as well as the required compatibility and interchangeability should be provided. Feedback from service now allows to quantify the advantages gained with an on-board life usage monitoring system in terms of spare part savings and flight safety increase. Furthermore the scatter in life consumption has been analysed and it can be concluded that the often heard opinion that life consumption is directly correlated with the mission type is not supported by the observations. Of course, it is possible to identify particular parameter constellations which occur under normal daily engine operation but cause either excessively high or very low life consumption. However, most of the scatter must be accepted to appear randomly. 1