MAINTENANCE ALLOCATION CHART (MAC)
7. Remove/Install. To remove and install the same item when required to perform service
or other maintenance functions. Install may be the act of emplacing, seating, or fixing
into position a spare, repair part, or module (component or assembly) in a manner to
allow the proper functioning of an equipment or system.
8. Replace. To remove an unserviceable item and install a serviceable counterpart in its
place. "Replace" is authorized by the MAC and assigned maintenance level is shown as
the third position code of the Source, Maintenance, and Recoverability (SMR) code.
9. Repair. The application of maintenance services, including fault location/troubleshooting,
removal/installation, disassembly/assembly procedures, and maintenance actions to
identify troubles and restore serviceability to an item by correcting specific damage, fault,
malfunction, or failure in a part, subassembly, module (component or assembly), end
item, or system.
The following definitions are applicable to the "repair" maintenance function services:
Inspect, test, service, adjust, align, calibrate, and/or replace.
Fault location/troubleshooting. The process of investigating and detecting the cause of
equipment malfunctioning; the act of isolating a fault within a system of Unit Under Test
Disassembly/assembly. The step-by-step breakdown (taking apart) of a spare/functional
group coded item to the level of its least component, that is assigned an SMR code of the
level of maintenance under consideration (i.e., identified as maintenance significant).
Actions. Welding, grinding, riveting, straightening, facing, machining, and/or resurfacing.
10. Overhaul. That maintenance effort (service/action) prescribed to restore an item to a
completely serviceable/operational condition as required by maintenance standards in
appropriate technical publications. Overhaul is normally the highest degree of
maintenance performed by the Army. Overhaul does not normally return an item to "like
11. Rebuild. Consists of those services/actions necessary for the restoration of
unserviceable equipment to a "like new" condition in accordance with original
manufacturing standards. Rebuild is the highest degree of material maintenance applied
to Army equipment. The rebuild operation includes the act of returning to zero those age
measurements (e.g., hours/miles) considered in classifying Army equipment/components.
Explanation of Columns in the MAC
Column (1) Group Number. Column (1) lists FGC numbers, the purpose of which is to identify
maintenance significant components, assemblies, subassemblies, and modules with the Next
Higher Assembly (NHA).
Column (2) Component/Assembly. Column (2) contains the item names of components,
assemblies, subassemblies, and modules for which maintenance is authorized.