ARMY TM 9-2815-259-24 AIR FORCE TO 38G1-125-2 MARINE CORPS 09249A/09246A-24 B-1 MAINTENANCE ALLOCATION CHART Section I. INTRODUCTION B.1   The Army Maintenance System MAC: a. This introduction (section I) provides a general explanation of all maintenance and repair functions authorized at various maintenance levels under the standard Army Maintenance System concept. b. The Maintenance Allocation Chart (MAC) in section II 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 will be consistent with the capacities and capabilities of the designated maintenance levels, which are shown in the MAC in column (4) as: Unit - includes two subcolumns, C (operator/crew) and O (unit) maintenance. Direct Support - includes an F subcolumn. General Support - includes an H subcolumn. Depot - includes a D subcolumn. c. Section III lists the tools and test equipment (both special tools and common tool sets) required for each maintenance function as referenced from section II. d. Section IV contains supplemental instructions and explanatory notes for a particular maintenance function. B.2  Maintenance Functions.   Maintenance Functions are 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 (i.e., by sight, sound, or feel).   b. Test. To verify serviceability by measuring the mechanical or electrical characteristics of an item and comparing those characteristics with prescribed standards.   c. 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. d. Adjust.  To maintain or regulate, within prescribed limits, by bringing into proper 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 performance. 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.