A real-time life-use consumption monitor is proposed for aircraft engine systems. The life monitor will process power data available on the aircraft to calculate the accumulating in-flight power loading which the engine experiences. This power loading reduces the available life of the engine. Under emergency in-flight conditions and/or foreign object damage, engine loads and temperatures can increase rapidly as a sign of decreased remaining engine life and reliability. The life monitor will calculate and display in the aircraft the remaining time for safe operation under these conditions. At present, fatigue life analysis techniques are primarily used as design-analysis tools These techniques have not been adapted for in-service use with an aircraft to date. The reliable use of aircraft engines can be extended with more accurate knowledge of their remaining component and system fatigue lives. Early identification of engines in need of repair due to heavy use will improve their in-service safety. By developing a life monitoring system which can be associated with a specific engine system and have as input the loads and load durations of that system, the reliability and safety of that system can be improved.