Appendix B. MAINTENANCE ALLOCATION CHART (MAC)

TM 55-1905-223-24-17

Appendix B. MAINTENANCE ALLOCATION CHART (MAC)

Section I. INTRODUCTION

B-1 THE ARMY MAINTENANCE SYSTEM MAC.

a This introduction (Section I) 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 in 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 tools 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 as referenced from Section II.

B-2 MAINTENANCE FUNCTIONS . 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 (i. e. , 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 decontamination, when required), to replace filters, 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 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.

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 3rd position code of the SMR code.

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