TM 10-3930-653-14&P 3.  Column Entries: Columns used in the MAC are explained below: a. Column 1 Group Number: Column One (1) lists group numbers, the purpose of which is to identify components, assemblies, subassemblies and modules with their next higher assemblies. b. Column   2   Component/Assembly:   Column   Two   (2)   contains   the   noun   names   of   components,   assemblies, subassemblies and modules for which maintenance is authorized. c. Column  3  Maintenance  Functions:  Column  Three  (3)  lists  the  functions  to  be  performed  on  the  item  listed  in Column 2. d. Column   4   Maintenance   Category:   Column   Four   (4)   specifies,   by   the   listing   of   a   "work   time"   figure   in   the appropriate subcolumn(s), the category 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 category of maintenance.  If the number   or   category   of   the   tasks   within   the   listed   maintenance   function   vary   at   different   maintenance   categories, appropriate "work time" figures will be shown for each category.  The number of man-hours specified by 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, troubleshooting  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 chart.  This figure does not include any time for performance of preliminary tasks listed elsewhere in the MAC, e.g., removal of engine under repair of fuel pump when the engine is listed separately in the MAC. B-12