TM 5-3810-290-24P 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. M -(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 ML-(Made at Spe- ON CODE (UOC) column and cialized Repair listed in the Bulk Material group Activity (SRA)) of the repair parts list in this MD-(Made at RPSTL.  If the item is authorized Depot) to you by the 3d position code of 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 AL-(Assembled item,  but  the  source  code by SRA) indicates the item is assembled AD-(Assembled by at a higher level, order the item Depot) from  the  higher  level  of 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 mainte- nance. 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, re- place, 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 low- est 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