Evolutionary maintenance for aircraft engines

This paper looks at the concept of evolutionary maintenance. This approach is especially useful for expensive, complex systems, such as aircraft engines. In evolutionary maintenance, the maintenance and inspection schedule is adjusted after every service activity. The requires knowledge of the time-to-failure of each module of the engine and the corresponding hard lives of any of its components if applicable. After every maintenance and inspection activity, the hard life and preventive maintenance schedule are revised by adjusting the maintenance interval without increasing the risk of failure (risk initially committed by selecting a maintenance policy). The paper compares the effectiveness of the evolutionary maintenance against the traditional approach based on the required reliability or acceptable number of failures between maintenance.