MAINTENANCE ALLOCATION CHART (MAC) INTRODUCTION
THE ARMY MAINTENANCE SYSTEM (MAC)
This introduction provides a general explanation of all maintenance and repair functions authorized at
various maintenance levels under the standard Army Maintenance System concept.
The Maintenance Allocation Chart (MAC) (immediately following the 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, 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.
The tools and test equipment requirements (immediately following the MAC) list the tools and test
equipment (both special 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:
1. 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).
This includes scheduled inspection and gagings and evaluation of cannon tubes.
2. 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.
3. 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. This includes scheduled exercising and purging of recoil mechanisms.
4. Adjust. To maintain or regulate, within prescribed limits, by bringing into proper position, or by
setting the operating characteristics to specified parameters.
5. Align. To adjust specified variable elements of an item to bring about optimum or desired
6. 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.
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
8. Replace. To remove an unserviceable item and install a serviceable counterpart in its place.
Replace is authorized by the MAC and assigned maintenance level is shown as the third position code of
the Source, Maintenance and Recoverability (SMR) code.