MAINTENANCE ALLOCATION CHART (MAC) INTRODUCTION (Contd)
Maintenance functions are limited to and defined as follows:
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
Test. To verify serviceability by measuring the mechanical, pneumatic, hydraulic, or electrical
characteristics of an item and comparing those characteristics with prescribed standards on a
scheduled basis, i.e., load testing of lift devices and hydrostatic testing of pressure hoses.
Service. Operations required periodically to keep an item in proper operating condition; i.e., to
clean (includes decontamination, when required), to preserve, to drain, to paint, or to replenish
fuel, lubricants, chemical fluids, or gases. This includes scheduled exercising and purging of
Adjust. To maintain or regulate, within prescribed limits, by bringing into proper position, or by
setting the operating characteristics to specified parameters.
Align. To adjust specified variable elements of an item to bring about optimum or desired
Calibrate. To determine and cause corrections to be made or to be adjusted on instruments or
test, measuring, and diagnostic equipment used in a 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.
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 an
equipment or system.
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.
The following definitions are applicable to the repair
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
Disassembly/assembly The step-by-step breakdown (taking apart) of a spare/functional
group coded item to the level of its least component, that is assigned an SMR code for the
level of maintenance under consideration (i.e., identified as maintenance significant).
Actions Welding, grinding, riveting, straightening, facing, machining, and/or resurfacing.