MAINTENANCE ALLOCATION CHART (MAC) INTRODUCTION
THE ARMY MAINTENANCE SYSTEM MAC
This introduction provides a general explanation of all maintenance and repair functions authorized at the two mainte-
nance levels under the Two-Level Maintenance System concept.
The MAC immediately following this introduction designates overall authority and responsibility for the performance
of maintenance functions on the identified end item or component. The application of the maintenance functions to the
end item or component shall be consistent with the capacities and capabilities of the designated maintenance levels,
Field - includes subcolumns:
C - Operator/Crew
O - Unit
F - Direct Support
Sustainment - includes subcolumns:
H - General Support
D - Depot
The tools and test equipment requirements (immediately following the MAC) list the tools and test equipment (both spe-
cial tools and common tool sets) required for each maintenance function as referenced from the MAC.
The remarks (immediately following the tools and test equipment requirements) contain supplemental instructions and
explanatory notes for a particular maintenance function.
Maintenance functions are limited to and defined as follows:
Inspect. To determine the serviceability of an item by comparing its physical, mechanical, and/or electrical characteris-
tics with established standards through examination (e.g., by sight, sound, or feel).
Test. To verify serviceability by measuring the mechanical, pneumatic, hydraulic, or electrical characteristics of an item
and comparing those characteristics with prescribed standards on a scheduled basis, i.e., load testing of lift devices and
hydrostatic testing of pressure hoses.
Service. Operations required periodically to keep an item in proper operating condition; e.g., to clean (includes decon-
taminate, when required), preserve, drain, paint, or replenish fuel, lubricants, chemical fluids, or gases.
Adjust. To maintain or regulate, within prescribed limits, by bringing into proper position, or by setting the operating
characteristics to specified parameters.
Align. To adjust specified variable elements of an item to bring about optimum or desired performance.
Calibrate. To determine and cause corrections to be made or to be adjusted on instruments of test, measuring, and diag-
nostic equipment used in precision measurement. Calibration 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
Remove/Install. To remove and install the same item when required to perform service or other maintenance functions.
Installation may be the act of emplacing or seating a spare, repair part, or module (component or assembly) into position
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. Replacement 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. Repair is 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.