MAINTENANCE ALLOCATION CHART
Section I. INTRODUCTION
a. This section provides a general explanation of all maintenance and repair functions authorized
at various maintenance categories.
b. The Maintenance Allocation Chart (MAC) in Section II designates overall authority and
responsibility for the performance of maintenance functions on Auxiliary Power Unit (APU). The
application of maintenance functions to the generator sets or components will be consistent
with the capacities and capabilities of the designated maintenance categories.
c. Section III lists the tools and test equipment (both special tools and common tool sets) required
for each maintenance function as referenced for Section II.
d. Section IV contains supplemental instructions and explanatory notes for particular maintenance
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 (e.g., by sight, sound,
b. Test. To verify serviceability and to detect incipient failure by measuring the mechanical or
electrical characteristics of an item and comparing those characteristics with prescribed
c. Service. Operations required periodically to keep an item in proper operating condition, i.e., to
clean (decontaminate), to preserve, to drain, to paint, or to replenish fuel, lubricants, chemical
fluids, or gases.
d. Adjust. To maintain, 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
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 the equipment or system.