Calibrate. To determine and cause corrections to be made or to be adjusted on instruments or test,
measuring, and diagnostic equipments used in precision measurement. Consists of comparisons of two
instruments, one of which is a certified standard of known accuracy, to detect and adjust any discrepancy in
the accuracy of the instrument being compared.
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
Replace. To remove an unserviceable item and install a serviceable counterpart in its place. Replace is
authorized by the MAC, and is shown as the 3rd position code of the Source, Maintenance, and
Recoverability (SMR) code.
Repair. The application of maintenance services, including fault location/troubleshooting,
removal/installation, and 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.
Overhaul. That maintenance effort (service/action) prescribed to restore an item to a completely
serviceable/operations condition, as required by maintenance standards in the appropriate technical
publications (i.e., DMWR). Overhaul is normally the highest degree of maintenance performed by the Army.
Overhaul does not normally return an item to like new condition.
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
materiel maintenance applied to Army equipment. The rebuild operation includes the act of returning to zero
those age measurements (hours, miles, etc.) considered in classifying Army equipment/components.
EXPLANATION OF COLUMNS IN THE MAC
Column 1, Group Number. Column 1 lists functional group code numbers, the purpose of which is to
identify maintenance significant components, assemblies, subassemblies, and modules with the next higher
assembly. End item group number shall be listed as 00.
Column 2, Component/Assembly. Column 2 contains the names of the components, assemblies,
subassemblies, and modules for which maintenance is authorized.
Column 3, Maintenance Function. Column 3 lists the functions to be performed on the item listed in
Column 2. (For detailed explanation of these functions, see the Maintenance Functions information detailed
Column 4, Maintenance Level. Column 4 specifies, by the listing of work-time in the appropriate sub
column(s), the level of maintenance authorized to perform the function listed in Column 3. This figure
represents the active time required to perform that maintenance function at the indicated level of
maintenance. If the number of complexity of the tasks within the listed maintenance function varies at
different maintenance levels, appropriate work-time figures will be shown for each level. The work-time figure
represents the average time required to restore an item (assembly, subassembly, component, module, end
item, or system) to a serviceable condition under typical field operating conditions.