Downloaded from https://www.everyspec.com ADS-79D-HDBK Health Indicator (HI): An indicator for needed maintenance action resulting from the combination of one or more CI values. Health Monitoring System: Equipment / techniques / procedures by which selected incipient failure or degradation can be determined. Legacy Aircraft: An aircraft in an operational unit that has passed its scheduled IOC (initial operational capability). Loads Monitoring: Equipment, techniques, or procedures used to measure the loads (forces or moments) experienced by an aircraft component during operational flight. Mission Profile:
A time-based description of engine operating conditions experienced in the course of a nominal mission. Physics of Failure: The physical phenomena that are analytically defined and describe the process by which a mechanical component fails during operation. Prognosis: The prediction of life/degradation of a component or the time before failure based on the current and accumulated parameter data. Regimes: Aircraft load event categorized by aircraft configuration, flight environment, and operating condition type and severity. Regime Recognition: The process of using flight data to identify historical flight regime occurrences and durations. Reliability:
The calculated statistical probability that a functional unit will perform its required function for a specified interval under stated conditions. Remaining Useful Life (RUL): The actual or predicted useful life left on a component at a particular time of operation. . Service Life: The number of hours or cycles a life-limited component may remain in service before it must be removed. Standard Deviation: A measure of the amount by which measurements deviate from their mean. Top of Scatter: Flight load records/ summary data which produce the highest fatigue damage for a given regime or load cycle when used in accordance with a given fatigue methodology. True Negative:
A fault is not indicated by the Digital Source Collector nor found to exist by inspection. True Positive: A fault is indicated by the Digital Source Collector and found to exist by inspection. Usage Monitoring System: Equipment / techniques / procedures by which selected aspects of service [flight] history can be determined. 7