| Recently, system owners and operators have emphasized the actual amount of time equipment is capable of performing its intended function. This emphasis results from increased: (1) consolidation of tasks to single equipment, (2) criticality of information, and (3) cost of ownership. Consequently, both the private and public sector have expanded the importance of system availability.; With military systems, increasing complexity, longer service life requirements, and reduced periodic maintenance and checkouts have increased system availability requirements. However, these factors compound the difficulty in estimating the system's true availability.; With dormant or semi-dormant systems, the amount of time a system "appears" available may differ from the "real" availability. The difference in "real" and "apparent" availability is often the result of a transition from an operational but dormant state to an inoperational but dormant state.; This research focused upon developing methodology to estimate the "real" availability for the Small ICBM weapon system, a key system in President Reagan's Strategic Modernization Program. The Small ICBM availability problem crosses the lines of the three traditional availability definitions. To redress this deficiency, a new class of availability referred to as "complex" availability was developed.; Major contribution. The major contributions of this research were: (1) the development of the concept of "complex" availability which applies to systems which combine two or more elements of instantaneous, mission or system, or steady-state availability, and (2) the development of a modeling technique to estimate the "real" availability for a system which falls into the category of "complex" availability.; The model's unique features included: (1) the capturing the non-available time due to transition from the operational but dormant state to an operative but dormant state, (2) test equipment which was not 100 percent capable of detecting failures, (3) the possibility test equipment may induce failures which may not be detected, (4) not all subsystems are restored to "like new" during maintenance, and (5) the occurrence of multiple failures. |
