ARMY TM 9-2815-253-24 AIR FORCE TO 38G1-93-2 MARINE CORPS TM 2815-24/3 B-3.  EXPLANATION OF COLUMNS IN THE MAC, SECTION II. a. Column 1, Group Number.  Column 1 lists functional group code numbers, the purpose of which are to identify maintenance significant components, assemblies, subassemblies, and modules with the next higher assembly.  End item group number shall be "00". b. Column    2,    Component    Assembly.        Column    2    contains    the    item    names    of    components,    assemblies, subassemblies, and modules for which maintenance is authorized. c. Column 3, Maintenance Function.  Column 3 lists the functions to be performed on the item listed in column 2. (For detailed explanation of these functions, see paragraph B-2.) d. Column  4,  Maintenance  Level.    Column  4  specifies,  by  the  listing  of  a  work  time  figure  in  the  appropriate subcolumn(s), the level of maintenance authorized to perform the function listed in column 3.  This figure represents the active  time  required  to  perform  that  maintenance  function  at  the  indicated  level  of  maintenance.    If  the  number  or complexity of the tasks within listed maintenance function vary at different maintenance categories, appropriate work- time figures will be shown for each category.  The work time figure represents the average time required to restore an item (assembly, subassembly, component, module, end item, or system) to a serviceable condition under typical field operating   conditions.      This   time   includes   preparation   time   (including   any   necessary   disassembly/assembly   time), troubleshooting/fault location time, and quality assurance/quality control time in addition to the time required to perform the specific tasks identified for the maintenance functions authorized in the Maintenance Allocation Chart.  The symbol designations for the various maintenance categories are as follows: C.................................. Operator or crew Maintenance O.................................. Organizational Maintenance F .................................. Direct Support Maintenance H.................................. General Support Maintenance D.................................. Depot Maintenance e. Column 5, Tools and Equipment.  Column 5 specifies, by code, those common tools sets (not individual tools), common TMDE, and special support equipment required to perform the designated function. f. Column 6, Remarks.  This column shall, when applicable, contain a letter code, in alphabetical order, which is keyed to the remarks contained in SECTION IV. B-4.  EXPLANATION OF COLUMNS IN TOOL AND TEST EQUIPMENT REQUIREMENTS, SECTION III. a. Column  1,  Reference  Code.    The  tool  and  test  equipment  reference  code  correlates  with  a  code  used  in  the MAC, SECTION II, Column 5. b. Column  2,  Maintenance  Category.    The  lowest  category  of  maintenance  authorized  to  use  the  tool  or  test equipment. c. Column 3, Nomenclature.  Name or identification of the tool or test equipment. d. Column 4, National Stock Number.  The National Stock Number of the tool or test equipment. e. Column 5, Tool Number.  The manufacturer's part number of the tool or test equipment. B-5.  EXPLANATION OF COLUMNS IN REMARKS, SECTION IV. a. Column 1, Reference Code.  The code recorded in column 6, SECTION II. b. Column  2,  Remarks.    This  column  lists  information  pertinent  to  the  maintenance  function  being  performed  as indicated in the MAC, SECTION II. B-2