TM 10-5410-228-24
MAINTENANCE ALLOCATION CHART (MAC)
Section I. INTRODUCTION
a. This introduction provides a general explanation of all maintenance and repair functions authorized
at the two maintenance levels under the Two-Level Maintenance System concept.
b. The 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:
Field - includes two columns, Unit maintenance and Direct Support maintenance. The Unit
maintenance column is divided again into two more sub-columns, C Operator or Crew and O for
Unit maintenance.
Sustainment - includes two subcolumns, General Support (H) and Depot (D).
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.
Maintenance functions are 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 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 which required to perform service or other
maintenance functions. Install may be the act of placing, 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 assigned maintenance level is shown as the third position code of the
Source, Maintenance and Recoverability (SMR) code.
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