h. 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 d position code of the 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. The maintenance effort (service/action) prescribed to restore an item to a completely
serviceable/operational condition as required by maintenance standards in 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.
k. Rebuild. Consists of those service/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 or returning to zero those age
measurements (hours, miles, etc.) considered in classifying Army equipments/components.
B-3. Explanation of Columns in the MAC, Section II.
a. 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 "00."
b. Column 2, Component/Assembly. Column 2 contains the names of components, assemblies, subassemblies,
and modules for which maintenance is authorized.
c. 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 paragraph B-2.)
d. Column 4, Maintenance Category. Column 4 specifies, by the listing of a work time figure in the appropriate
subcolumn(s), the category 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 category of maintenance. If the number or
complexity of the tasks within the listed maintenance function vary at different maintenance categories, appropriate work
time figures will be shown for each category. 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. This time includes preparation time (including any necessary disassembly/assembly time),
troubleshooting/fault location time, and quality assurance/quality control time in addition to the time required to perform
the specific tasks identified for the maintenance functions authorized in the maintenance allocation chart. The symbol
designations for the various maintenance categories are as follows:
Aviation Unit Maintenance
Aviation Intermediate Maintenance
e. Column 5, Tools and Equipment. Column 5 specifies, by code, those common tool sets (not individual tools)
and special tools, TMDE, and support equipment required to perform the designated function.