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 third 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.
B-3. Explanation of Columns in the MAC, Section II.
Column 1, Group Number. Column 1 lists functional group code numbers, the purpose of which is to identify
maintenance of significant components, assemblies, and subassemblies, with the next higher assembly. End item group
number is "00".
Column 2, Component/Assembly. Column 2 contains the names of components, assemblies, and
subassemblies 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 paragraph B-2).
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. The work time
figure represents the average time required to restore an item (assembly, subassembly, component, or end item) to a
serviceable condition under typical field operating conditions.
Column 5, Tools and Equipment. Column 5 specifies, by code, those common tool sets (not individual tools)
and support equipment required to perform the designated function.
Column 6, Remarks. This column shall, when applicable, contain a letter code, in alphabetical order, which
shall be keyed to the remarks contained in Section IV.
B-4. Explanation of Columns in Tool and Test Equipment Requirements, Section III.
Column 1, Reference Code. The tool and test equipment reference code correlates with a code used in the
MAC, Section II, Column 5.
Column 2, Maintenance Category. The lowest category of maintenance authorized to use the tool. The "O"
code corresponds to Aviation Unit Maintenance (AVUM), and the '"F" code corresponds to