TM 9-4940-421-14
MAINTENANCE
ALLOCATION
CHART
Section I. I N T R O D U C T I O N
C-1 GENERAL.
i. Repair. The application of maintenance services
or other maintenance actions to restore serviceability
a. This section provides a general explanation of all
m a i n t e n a n c e and repair functions authorized at
to an item by correcting specific damage, fault, mal-
function, or failure in a part, subassembly, module
various maintenance levels.
b. The Maintenance Allocation Chart (MAC) in Sec-
(component or assembly), end item, or system.
tion II, designates overall responsibility for the per-
i. Overhaul. T h a t m a i n t e n a n c e e f f o r t ( s e r -
formance of maintenance functions on the identified
vices/actions) necessary to restore an item to a com-
end item or component. The implementation of the
pletely serviceable/operational condition as prescribed
by maintenance standards (i.e., DMWR) in appropriate
maintenance functions upon the end item or compo-
technical publications. Overhaul is normally the high-
nent, will be consistent with the assigned maintenance
functions.
est degree of maintenance performed by the Army.
Overhaul does not normally return an item to like new
c. Section HI lists the special tools and test equip-
condition.
ment required for each maintenance function as refer-
enced from Section II.
k. Rebuild. Consists of those services/actions neces-
sary for the restoration of unserviceable equipment to
d. Section IV contains supplemental instructions on
explanatory notes for a particular maintenance func-
a like new condition in accordance with original
tion.
m a n u f a c t u r i n g standards. Rebuild is the highest
degree of materiel maintenance applied to Army
C-2. MAINTENANCE FUNCTIONS.
equipment. The rebuild operation includes the act of
a. Inspect. To determine the serviceability of an
returning to zero those age measurements (hours/miles,
item by comparing its physical, mechanical and/or
e t c . ) considered in classifying Army equip-
electrical characteristics with established standards
ment/components.
through examination.
b. Test. To verify serviceability and detect incipient
C-3. COLUMN ENTRIES USED IN THE MAC.
failure by measuring the mechanical or electrical
a. Column 1, Group Number. Column 1 lists group
numbers, the purpose of which is to identify compo-
characteristics of an item and comparing those charac-
nents, assemblies, subassemblies and modules with the
teristics with prescribed standards.
next higher assembly.
c. Service. Operations required periodically to keep
an item in proper operating condition, i.e., to clean (de-
b. Column 2, Component/Assembly. Column 2 con-
contaminate), to preserve, to drain, to paint, or to
tains the names of components, assemblies, subassem-
replenish fuel, lubricants, hydraulic fluids, or com-
b l i e s , and modules for which maintenance is
pressed air supplies.
authorized.
d. Adjust To maintain, within prescribed limits, by
c. Column 3, Maintenance Functions. Column 3 lists
bringing into proper or exact position, or by setting the
the functions to be performed on the item listed in col-
umn 2. (For detailed explanation of these functions, see
operating characteristics to specified parameters.
e. Align. Adjust specified variable elements of an
item to bring about optimum or desired performance.
d. Column 4, Maintenance Level. C o l u m n 4
f. Calibrate. To determine and cause corrections to
specifies by listing of a "work time" figure in the ap-
.
propriate subcolumn(s) the lowest level of maintenance
be made or to be adjusted on instruments or test
measuring and diagnostic equipments used in precision
authorized to perform the function listed in Column 3.
This figure represents the active time required to per-
measurements. Consists of comparisons of two instru-
.
form the maintenance function at the indicated level of
ments, one of which is a certified standard of known
maintenance. If the number or complexity of the tasks
accuracy, to detect and adjust any discrepancy in the
w i t h i n the listed maintenance function vary at
accuracy of the instrument being compared.
g. Install The act of emplacing, seating or fixing
different maintenance levels, appropriate "work time"
figures will be shown for each level. The number of
into position an item, part, or module (component or as-
manhours specified by the "work time" figure repre-
sembly) in a manner to allow the proper functioning of
an equipment or system.
sents the average time required to restore an item (as-
sembly, subassembly, component, module, end item, or
h Replace. The-act of substituting a serviceable like
system) to a serviceable condition under typical field
type part, subassembly, or module (component or as-
operating conditions. This time includes preparation
sembly) for an unserviceable counterpart.
