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Organizations that utilize fleets of expensive repairable equipment are faced with numerous challenges related to the specification of maintenance policies and the allocation of maintenance resources. The associated maintenance decisions can have a drastic impact on fleet performance. Due to the significant acquisition costs associated with the components that comprise the units of equipment in the fleet, cannibalization is often used in the absence of available spare parts to enable fleet maintenance managers to satisfy fleet performance constraints such as readiness requirements. This research is focused on the development and analysis of a closednetwork, discrete-event simulation model that is used to assess the impacts of cannibalization, small spare parts inventories and maintenance-induced damage on a fleet of systems. Using numerical examples, we demonstrate the comparison between cannibalization and the investment in limited spare parts inventories. We evaluate fleet performance using average readiness and total maintenance cost. Specifically, we demonstrate that investments in spare parts inventories can reduce the need for and value of cannibalization. However, our results also support the use of cannibalization as a low-cost alternative to investing in expensive spare parts. We also explore the impact of damage induced by maintenance on fleet performance. Specifically, we demonstrate that maintenance-induced damage can reduce the benefit of cannibalization while drastically increasing maintenance expenditures.

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information , 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY)2. REPORT TYPE 3. DATES COVERED (From -To) ABSTRACTThe objective of this research is to investigate the use of a mathematical modeling methodology for integrating maintenance planning and sortie scheduling issues. First, the relevant research literature for both selective maintenance and fleet assignment is presented. Next, background research is presented, which extends a current selective maintenance model to incorporate sets of systems. Here a selective maintenance model for a set of systems that must execute a set of missions with system maintenance performed only between missions is defined. Finally, we formulate a more complex optimization model that addresses a more dynamic mission profile. Specifically, missions start and end at different times, and maintenance and scheduling decisions are made over a series of time "buckets." We consider a planning horizon such that each system in the set returns from its previous mission and begins its future mission; however, no system returns from its future before the end of the planning horizon. times; therefore, a maintenance manager must decide how to allocate the available resources. This allocation falls within the domain of selective maintenance. Selective maintenance is defined as the process of identifying the subset of maintenance activities to perform from a set of desired maintenance actions. Although the modeling of repairable equipment has been studied extensively, traditional studies tend to focus on a single system and ignore the mission profile of the system. For the United States Air Force (USAF), these limitations prevent current models from providing meaningful guidance relative to maintenance planning and sortie scheduling.The objective of this project is to investigate the use of a mathematical modeling methodology for integrating maintenance planning and sortie scheduling issues. First, the relevant research literature for both selective maintenance and fleet assignment is presented. The selective maintenance literature is limited in that current models only consider a single system, and most of the fleet assignment literature is motivated by the com...

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