TM 5-3805-254-20P 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 re- KD quisitioned individually.  They are part of a kit KF which  is authorized to the maintenance KB 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 Level) the DESCRIPTION AND USABLE ON  CODE (UOC) column and listed in the Bulk ML-(Made at Spe- Material group of the repair cialized Repair parts list in this RPSTL.  If the Activity (SRA)) item is authorized you by the 3d MD-(Made at    to position code of the SMR code, Depot) but the source code indicates it is made at a higher level, order the item from the higher level of maintenance. AO-(Assembled by Items with these codes are not to UM/AVUM be requested/requisitioned Level) individually.  The parts that make AF-(Assembled by up the assembled item must be DS/AVIM requisitioned or fabricated and Level) assembled at the level of AH- (Assembled by maintenance indicted by the GS Category) source code.  If the 3d position code of the SMR code AL-(Assembled by authorizes you to replace the SRA) item, but the source code AD-(Assembled by indicates the item is assembled Depot) at a higher level, order the item 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 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. 2