Appendix D. MAINTENANCE ALLOCATION CHART.

TM 9-4931-378-13&P

APPENDIX D

MAINTENANCE ALLOCATION CHART.

Section I. INTRODUCTION

Repair. The application of maintenance services

D-1. General

or other maintenance actions to restore serviceability to an

item by correcting specific damage, fault, malfunction, or

This section provides a general explanation of all

failure in a part, subassembly, module (component or as-

maintenance and repair functions authorized at various

sembly), end item, or system.

maintenance levels.

That maintenance effort (services/ac-

b. The Maintenance Allocation Chart (MAC) in sec-

Overhaul.

tion II designates overall responsibility for the performance

tions) necessary to restore an item to a completely service-

of maintenance functions of the identified end item or

able/operational condition as prescribed by maintenance

component. The implementation of the maintenance func-

standards (i.e., DMWR) in appropriate technical publica-

tions upon the end item or component will be consistent

tions, Overhaul is normally the highest degree of mainten-

with the assigned maintenance functions.

ance performed by the Army. Overhaul does not normally

Section III lists the special tools and test equip-

return an item to like new condition.

ment required for each maintenance function as referenced

k. Rebuild. Consists of those services/actions neces-

from section II.

sary for the restoration of unserviceable equipment to a I ike

d. Section IV contains supplemental instructions and

new condition in accordance with original manufacturing

explanatory notes for a particular maintenance function.

standards. Rebuild is the highest degree of material mainte-

nance applied to Army equipment. The rebuild operation

D-2. Maintenance Functions

includes the act of returning to zero those age measure-

ments (hours/weeks, etc) considered in classifying Army

Inspect.

To determine the serviceability of an

equipments/components.

item by comparing its physical, mechanical and/or electrical

characteristics with established standards through examina-

D-3. Explanation of Columns in the MAC, Section Il.

tion.

Column 1, Group Number. Column 1 lists group

b. Test. To verify serviceability and detect incipient

failure by measuring the mechanical or electrical character-

numbers, the purpose of which is to identify components,

istics of an item and comparing those characteristics with

assemblies, subassemblies, and modules with the next

higher assembly.

prescribed standards.

b. Column 2, Component/Assembly. Column 2 con-

c. Service. Operations required periodically to keep

tains the names of components, assemblies, subassembly ies,

an item in proper operating condition, i.e., to clean (decon-

and modules for which maintenance is authorized.

taminate), to preserve, to paint, or to replenish lubricants.

Column 3, Maintenance Functions.

Column 3

d. A d j u s t To maintain, with prescribed limits, by

Iists the functions to be performed on the item listed in

bringing into proper or exact position, or by setting the

column 2. (For detailed explanation of these functions, see

operating characteristics to specified parameters.

e. AIign.

To adjust specified variable elements of an

para. D-2).

d. Column 4, Maintenance Level. Column 4 Speci-

item to bring about optimum or desired performance.

f. Calibrate. To determine and cause corrections to

fies, by the listing of a "work-time" figure in the appropri-

be made or to be adjusted on instruments or test measuring

ate subcolumn(s), the lowest level of maintenance autho-

and diagnostic equipment used in precision measurement.

rized to perform the function listed in column 3. This fig-

Consists of comparisons of two instruments, one of which

ure represents the active time required to perform the

is a certified standard of known accuracy, to detect and

maintenance function at the indicated level of maintenance.

adjust any discrepancy in the accuracy of the instrument

If the number or complexity of the tasks within the listed

being compared.

maintenance function vary at different maintenance levels,

appropriate " w o r k t i m e " figures will be shown for each

9. Install. The act of emplacing, seating, or fixing in-

to position an item, part, or module (component or assem-

level. The number of manhours specified by the "work

bly) in a manner to allow the proper functioning of an

time" figure represents the average time required to restore

equipment or system,

an item (assembly, subassembly, component, module, end

h. Replace. The act of substituting a serviceable like

item, or system) to a serviceable condition under typical

field operating conditions. This time includes preparation

type part, subassembly, or module (component or assem-

time, troubleshooting time, and quality assurance/quality

bly) for an unserviceable counterpart.

D-1