Philosophy and assumptions:
The maintainability procedures presented here permit analyzing the maintainability of electronic equipment/systems including direct accountability of diagnostics/isolation/test capabilities, replaceable item construction (a replaceable item (RI) us any of those physical entities normally removed and replaced to effect repair at the maintenance level for which the prediction is being made) packaging, and component failure rates.
Replaced/Superseded by document(s)
The prediction of the expected number of hours that a system or device will be in an inoperative or 'down state' while it is undergoing maintenance is of vital importance to the user because of the adverse affect that expressive downtime has on a mission success. Therefore, once the operational requirements of a system are fixed, it is imperative that a technique be utilized to predict its maintainability in quantitative terms as early as possible during the design phase. This prediction should be updated continuously as the design progresses to assure a high probability of compliance with specified requirements.