Section I. INTRODUCTION
The Army Maintenance System MAC
This introduction provides a general explanation of all maintenance and repair functions authorized at the two
maintenance levels under the Two-Level Maintenance System concept.
The MAC (immediately following the introduction) designates overall authority and responsibility for the
performance of maintenance functions on the identified end item or component. The application of the
maintenance functions to the end item or component shall be consistent with the capacities and capabilities
of the designated maintenance levels, which are shown on the MAC in column (4) as:
Field - includes two columns, Unit maintenance and Direct Support maintenance. The Unit maintenance
column is divided again into two more subcolumns, C for Operator or Crew and O for Unit maintenance.
Sustainment includes two subcolumns, General Support (H) and Depot (D)
The tools and test equipment requirements (immediately following the MAC) list the tools and test equipment
(both special tools and common tool sets) required for each maintenance function as referenced from the MAC.
The remarks (immediately following the tools and test equipment requirements) contain supplemental instructions
and explanatory notes for a particular maintenance function.
Maintenance functions are limited to and defined as follows:
1. 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 feel.) This
includes scheduled inspection and gagings and evaluation of cannon tubes.
2. 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.
3. Service. Operations required periodically to keep an item in proper operating condition, e.g. to clean
(includes decontaminate, when required), to preserve, to drain, to paint, or to replenish fuel, lubricants,
chemical fluids, or gases. This includes scheduled exercising and purging of recoil mechanisms. The
following are examples of service functions:
a. Unpack. To remove from packing box for service or when required for the performance of
b. Repack. To return item to packing box after service and other maintenance operations.