B-1. THE ARMY MAINTENANCE SYSTEM (MAC)
B-2. MAINTENANCE FUNCTIONS
TM 9-2320-280-20-3
APPENDIX B
MAINTENANCE ALLOCATION CHART
Section I. INTRODUCTION
a. This section provides a general explanation of all maintenance and repair functions authorized at
various maintenance levels under the standard Army Maintenance System Concept.
b. The Maintenance Allocation Chart (MAC) in section II 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 will be consistent with the capacities and
capabilities of the designated maintenance levels, which are shown on the MAC in column (4) as:
Unit - includes two subcolumns, C (operator/crew ) and O
(unit) maintenance.
Direct Support - includes an F subcolumn.
General Support - includes an H subcolumn.
Depot - includes a D subcolumn.
c. Section III lists the tools and test equipment (both special tools and common tool sets) required for each
maintenance function as referenced from section II.
d. Section IV contains supplemental instructions and explanatory notes for a particular maintenance function.
Maintenance functions will be limited to and defined as follows:
a. Inspect. To determine the serviceability of an item by comparing its physical, mechanical, and/or
electrical characteristics with established standards through examination (e.g., by sight, sound, or feel).
b. Test. To verify serviceability by measuring the mechanical, pneumatic, hydraulic, or electrical
characteristics of an item and comparing those characteristics with prescribed standards.
c. Service. Operations required periodically to keep an item in proper operating condition, i.e., to clean
(includes decontaminate, when required), to preserve, to drain, to paint, or to replenish fuel, lubricants,
chemical fluids, or gases.
d. Adjust. To maintain or regulate, within prescribed limits, by bringing into proper or exact position, or
by setting the operating characteristics to specified parameters.
e. Align. To adjust specified variable elements of an item to bring about optimum or desired performance.
f. Calibrate. To determine and cause corrections to be made or to be adjusted on instruments or 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.
g. Remove/Install. To remove and install the same item when required to perform service or other
maintenance functions. Install maybe 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.
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 3d position code of the SMR code.
B-1
