TM 10-3930-618-24P 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 maintenance category indicated in the 3d KB 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 LEVEL 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 UMI AVUM up the assembled item must be Level) requisitioned or fabricated and AF-(Assembled by assembled at the  level of DSIAVIM 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 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  CAGE  and  part  number  given,  if  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. F - Direct support or aviation intermediate  level  can remove, replace, and use the item. H - General support  level  can  remove,  replace,  and use the item. L - Specialized  repair activity can remove,  replace, and use the item. D - Depot  level  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. 2