LRCA—Local Repair Cycle Asset—Any repairable item in an activity’s OSI or fixed allowance for which local repair capability exists. LUI—Life Usage Index—A measurement which determines the life of an engine based on thermal and dynamic loads experienced during engine operation. MAF—Maintenance Action Form—A multi-purpose document used in the MDS and the VIDS. MAG—Marine Aircraft Group. MAGNETIC PARTICLE—A method that uses magnetic fields for the purpose of detecting fine discontinuities at or near the surface of the part. This method is limited to ferromagnetic materials. MAINTAINABILITY —The ability to maintain an item in, or restore to, a specific operational condition by expending resources, including man-hours, at an acceptable rate when using prescribed procedures and resources. MAINTENANCE—The  function  of  retaining material in, or restoring it to, a serviceable condition. Its phases include servicing, repair, modification, modernization, overhaul, rebuild, test, reclamation, inspection, condition determination, and the initial provisioning of support items. The term has a very general meaning, ranging from a matter of minutes of squadron servicing, to a matter of months of industrial activity rework; the provision of maintenance material itself is within the meaning. Maintenance should be qualified to convey a specific meaning. MAINTENANCE (MATERIAL)—All actions taken to retain material in a serviceable condition or to restore it to serviceability. It includes inspection, testing, servicing, classification as to service- ability, repair, rebuilding, and reclamation. MAINTENANCE ACTION—Any one of a number of types of specific maintenance operations necessary to retain an item in or restore it to a specified condition. MAINTENANCE ACTIVITY—Any organization (activity or unit) of the naval establishment assigned the mission, task, or functional responsibility of performing aircraft upkeep or rework. Use of the term refers to organizations and personnel occupying aircraft maintenance facilities and using aircraft maintenance material but does not include reference to the facilities or material themselves. Aircraft maintenance activities are classified as to levels of maintenance performed. The highest level a particular activity is responsible for performing is established as the activity’s classification. This classification does not necessarily mean the activity involved is responsible for all lower levels of maintenance. MAINTENANCE CODE—Codes  assigned  to support items to indicate the maintenance levels authorized to remove and replace, repair, overhaul, assemble, inspect and test, and condemn items. Also assigned to maintenance tools and end items of SE to indicate the lowest level of maintenance requiring the item. MAINTENANCE CONCEPT—The planned or envisioned methods that will be employed to sustain the aeronautical system/equipment at a defined level of readiness or in a specified condition in support of the operational requirement. This includes significant aeronautical system/equipment characteristics; for example, built-in test, compatibility with existing or planned test and SE, and a generalization of logistics support element requirements (manpower, equipment, facilities, and workload distribution throughout the defined maintenance level). The maintenance concept is initially stated by the government for design and support planning purposes and provides the basis or point of departure for development of the plan to maintain. The maintenance concept may be influenced or modified by economic, technical, or logistics considerations as the design development of the aeronautical system/equipment proceeds. MAINTENANCE DEPARTMENT—The part of an activity responsible for the activity’s aircraft maintenance functions, also considered a maintenance activity. In the shore establishment, stations responsible for I-level maintenance will have maintenance departments. MAINTENANCE DEPTHS—The complexity or extensiveness of aircraft maintenance functions; for example, the extent of disassembly, the complexity of a test. MAINTENANCE DETACHMENT—The part of an aircraft maintenance activity geographically separated from but administered by the parent activity. AI-13