MAINTENANCE ALLOCATION CHART (MAC)Continued
Calibrate. To determine and cause corrections to be made or to be adjusted on instruments of 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.
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.
Replace. To remove an unserviceable item and install a serviceable counterpart in its place.
Replace is authorized by the MAC and the assigned maintenance level is shown as the third
position code of the Source, Maintenance and Recoverability (SMR) code.
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:
ServicesInspect, test, service, adjust, align, calibrate, and/or replace.
Fault location/troubleshootingThe process of investigating and detecting the
cause of equipment malfunctioning; the act of isolating a fault within a system
or Unit Under Test (UUT).
Disassembly/assemblyThe step-by-step breakdown (taking apart) of a spare/
functional group coded item to the level of its least component, that is assigned
a Source, Maintenance, and Recoverability (SMR) code for the level of
maintenance under consideration (e.g., identified as maintenance significant).
ActionsWelding, grinding, riveting, straightening, facing, machining, and/or
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.
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, etc.) considered in
classifying Army equipment/components.