Downloaded from https://www.everyspec.com MIL-HDBK-502: A MIL-HDBK-502: A CQUISITION CQUISITION L OGISTICS OGISTICS 6.2.2 Differences Between Detail And Performance Requirements Reliability Performance specifications would set requirements in terms of mean time between failure, operational availability, etc. Detail specifications may achieve reliability by requiring a known reliable design. Maintainability Performance specifications would specify requirements in terms of mean time to repair, maintenance frequency, skill levels of repair personnel, time required for maintenance, etc. Detail specifications may specify exact designs to accomplish maintenance actions.
Reliability and Maintainability Parameters Reliability and maintainability parameters affect readiness, mission success, manpower and maintenance costs, and other logistics support costs. For these categories reliability and maintainability can be expressed quantifiably as shown in Figure 6-1:
Reliability Maintainability Readiness mean time between mean time to (or availability) downing events restore system Mission Success mission time between mission time to (or dependability) critical failures restore functions Maintenance mean time between direct man-hours per Manpower Cost maintenance maintenance action Logistic Support Cost mean time between total cost to remove a part at demands all levels of maintenance Figure 6-1. Reliability and Maintainability 6-7