TM 9-2350-247-20-3
MAINTENANCE ALLOCATION CHART (MAC)
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INTRODUCTION
GENERAL
This section provides a general explanation of all maintenance and repair functions authorized at various maintenance levels.
The Maintenance Allocation Chart (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. They are:
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
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. sight, sound, or feel).
(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; e.g., 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 performance.
(6) 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.
(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) 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.
(9) 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.
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