MAINTENANCE ALLOCATION CHART (MAC)
test, measuring, and diagnostic equipment 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.
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. Paint. To prepare and spray color coats of paint so that the ammunition can be identified
and protected. The color indicating primary use is applied, preferably, to the entire exterior surface
as the background color of the item. Other markings are to be repainted as original so as to retain
9. Replace. To remove an unserviceable item and install a serviceable counterpart in its place
"Repair" is authorized by the MAC and assigned maintenance level is shown as the third position
code of the Source, Maintenance and Recoverability (SMR) code.
10. 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 case of equipment
malfunctioning; the act of isolating a fault within a system or Unit Under Test (UUT).
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 for the level of maintenance
under consideration (i.e., identified as maintenance significant).
Actions. Welding, grinding, riveting, straightening, facing, machining, and/or resurfacing.
11. 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 new condition.
12. 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).