In military acquisition, operational availability is used as one of the Key Performance Parameters in requirements documents, to form the basis for decision support analyses.
Formal reliability modeling during development is required to prioritize resource allocation before operation begins.
Estimated failure rates and logistics delay are used to identify the number of forward positioned spare parts required to avoid excessive down time.
For a system that is expected to be available constantly, the below operational availability figures translate to the system being unavailable for approximately the following lengths of time (when all outages during a year are added together): The following data is collected for maintenance actions while in operation to prioritize corrective funding.
This data is applied to the reliability block diagram to evaluate individual availability reduction contributions using the following formulas.