MAINTENANCE ALLOCATION CHART (MAC) INTRODUCTION CONTINUED
serviceability to an item by correcting specic damage, fault, malfunction, or failure in a part, subassem-
bly, module (component or assembly), end item, or system.
The following denitions are applicable to the "repair" maintenance function:
Services. Inspect, test, service, adjust, align, calibrate, and/or replace.
Fault location/troubleshooting. The process of investigating and detecting the cause of
equipment malfunctioning; the act of isolating a fault within a system or Unit Under Test
Disassembly/assembly. The step-by-step taking apart (or breakdown) of a spare/func-
tional group coded item to the level of its least component identied as maintenance
signicant (i.e., assigned an SMR code) for the level of maintenance under consideration.
Actions. Welding, grinding, riveting, straightening, facing, machining, and/or resurfacing.
11. Overhaul. That maintenance effort (service/action) prescribed to restore an item to a completely ser-
viceable/operational condition as required by maintenance standards in appropriate technical publica-
tions. Overhaul is normally the highest degree of maintenance performed by the Army. Overhaul does
not normally return an item to like new condition.
12. Rebuild. Those services/actions necessary for the restoration of unserviceable equipment to a like new
condition in accordance with original manufacturing standards. Rebuild is the highest degree of ma-
teriel maintenance applied to Army equipment. The rebuild operation includes the act of returning to
zero those age measurements (e.g., hours/miles) considered in classifying Army equipment/compo-
Explanation of Entries in the MAC
Group Number and Component/Assembly. The functional groupings in the sample below identify maintenance
signicant components, assemblies, subassemblies, and modules with the next higher assembly.
ENGINE, GENERAL Servicing, handling inspection requirements, overhaul
and retirement schedules. External lines and hoses. (As applicable.)
COMPRESSOR SECTION (COLD SECTION MODULE) Rotor, blades,
vanes, impeller, stators, inlet guide vanes, mainframe, particle separa-
tor, bleed valve, bearings, seals, external lines and hoses.
nozzles, stators, rotor, seals, couplings, blades.
POWER-TURBINE (POWER TURBINE MODULE) Nozzles,
rotors, blades, exit guide vanes, exhaust frame, drive
shaft, bearings, seals, external lines and hoses.
ACCESSORY GEAR BOX (ACCESSORY SECTION MODULE) Input and
output gears, seals, chip detector, housings, drive shaft, bearings.
FUEL SYSTEM Fuel control, fuel boost pump, governors, fuel lter assembly,
sequence valve, fuel manifold, fuel nozzle, external lines and hoses.
ELECTRICAL SYSTEM Electrical control units, exciters, thermocou-
ples, ignition harness, electrical cables, history record, torque over
speed sensor, Np sensor, external lines and hoses.
OIL SYSTEM Tanks, oil lter, oil cooler, lube and scavenger
pumps, oil lter bypass sensor, external lines and hoses.
Maintenance Function. Entry lists the functions to be performed on the items listed in Component/Assembly.