TM 5-3895-373-20 APPENDIX B MAINTENANCE ALLOCATION CHART (MAC) 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 on the MAC in column (4) as: Unit includes two subcolumns, C (operator/crew) and 0 (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. 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 standards. c. Service.      Operations   required   periodically   to keep an item in proper operating condition, i.e., to clean (includes    decontaminate,    when    required),    preserve, drain,  paint,  or  to  replenish  fuel,  lubricants,  chemical fluids, or gases. d. Adjust.    Maintain  or  regulate,  within  prescribed limits,  by  bringing  into  proper  or  exact  position,  or  by setting     the     operating     characteristics     to     specified parameters. e. Calibrate.        To    determine    the    cause    and corrections  to  be  made  or  adjusted  on  instruments  or test    measuring    and    diagnostic    equipment    used    in precision  measurement.    This  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. f. Replace.  To remove an unserviceable item and install a serviceable counterpart in its place.  Replace is authorized   by   the   MAC   and   is   shown   as   the   third position code of the SMR code. g. Repair.          The     application     of     maintenance services', including fault location/troubleshooting², removal/installation, disassembly/assembly procedures³, and   maintenance   actions⁴   to   identify   troubles,   and restore  serviceability  to  an  item  by  correcting  specific damage,    fault,    malfunction,    or    failure    in    a    part, subassembly,   module   (component   or   assembly),   and item or system. ¹ Services Inspect, test, service, adjust, align, calibrate, and/or replace. 2 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 (UUT). ³ 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). 4 Actions   Welding,   grinding,   riveting,   straightening, facing, machining, and/or resurfacing. B-1