TM 5-3805-255-20P SECTION I (1) Source Code.  The source code tells you how to get an item needed for maintenance, repair, or overhaul of an end item/equipment.  Explanations of source codes follows: Code Application/Explanation PA Stocked items; use the applicable NSN to PB request/requisition items with these source PC** codes.  They are authorized to the category PD indicated by the code entered in the 3d PE position of the SMR code. PF **  Items  coded  PC  are  subject  to PG deterioration. Items with these codes are not to be KD requested/requisitioned  individually.  They KF are part of a kit which is authorized to the KB maintenance category indicated in the 3d position of the SMR code.  The complete kit must be requisitioned and applied. MO-(Made at UM/ Items with these codes are not to AVUM Level) be requested/requisitioned MF-(Made at DS/ individually.  They must be made AVUM Level) from  bulk material which  is MH- (Made at GS identified by the part number in the DESCRIPTION AND USABLE ON CODE (UOC) column and ML-(Made at Spe- listed in the Bulk Material group cialized Repair of the repair parts list in this Activity (SRA)) RPSTL.  If the item is authorized MD-(Made at to you by the 3d position code of Depot) the SMR code, but the source code indicates it is made at a higher level, order the item from the higher level of maintenance. Items with these codes are not to be requested/requisitioned AO-(Assembled by individually.  The parts that make UM/ AVUM up the assembled item must be Level) requisitioned or fabricated and AF-(Assembled by assembled at the level  of DS/AVIM maintenance indicted by the Level) source code.  If the 3d position AH-(Assembled by code   of  the   SMR   code GS Category) authorizes you to replace the item,  but  the  source  code AL-(Assembled by indicates the item is assembled SRA) at a higher level, order the item AD-(Assembled by from  the  higher  level  of Depot) maintenance. XA - Do not requisition an "XA"-coded item.  Order its next higher assembly.  (Also refer to the NOTE following.) XB - If an "XB" item is not available from salvage, order it using the FSCM or CAGE and part   number given. XC- Installation drawing,  diagram,  instruction sheet, field service drawing, that is identified by the manufacturer’s part number. XD - Item is not stocked.  Order an "XD"-coded item through normal supply channels using the FSCM or CAGE and part number given, if I no NSN is available. NOTE:   Cannibalization   or   controlled   exchange,   when authorized, may be used as a source of supply for items with  the  above  source  codes,  except  for  those  source coded  "XA"  or  those  aircraft  support  items  restricted  by requirements of AR 700-42. (2) Maintenance Code.  Maintenance codes tell you the   level(s)   of   maintenance   authorized   to   USE   and REPAIR   support   items.      The   maintenance   codes   are entered in the third and fourth positions of the SMR code as follows: (a) The maintenance code entered in the third position tells you the lowest maintenance level authorized  to  remove,  replace,  and  use  an  item.    The maintenance    code    entered    in    the    third    position    will indicate  authorization  to  one  of  the  following  levels  of maintenance. Code Application/Explanation C - Crew or operator maintenance done within unit maintenance or aviation unit maintenance. O - Unit maintenance or aviation unit category can remove, replace, and use the item. (b) The    maintenance    code    entered    in    the fourth   position   tells   whether   or   not   the   item   is   to   be repaired and identifies the lowest maintenance level with the   capability   to   do   complete   repair   (i.e.,   perform   all authorized repair functions).  (NOTE: Some limited repair may be done on the item at a lower level of maintenance, if authorized by the Maintenance Allocation Chart (MAC) and  SMR  codes.)  This  position  will  contain  one  of  the following maintenance codes: Code Application/Explanation O - Unit maintenance or aviation unit is the lowest level that can do complete repair of the item. F - Direct support or aviation intermediate is the lowest level than can do complete repair of the item. H- Intermediate General support is the lowest level that can do complete repair of the item. Change 1  2