SECTION I TM 53810-232-20P (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 PG **Items coded PC are subject to deterioration. KD Items with these codes are not to be re- KF quested/requisitioned individually. They are KB part of a kit which is authorized to the 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 A VUM Level) to be requested/requisitioned individually. They must be MF-(Made at IDS/ made from bulk material which A VUM Level) is identified by the part numbers MH-(Made at IGS ber in the  DESCRIPTION Level ANDUSABLE  ON   CODE MH-(Made at IGS (UOC) column and listed in Level) the Bulk Material group of the ML-(Made at Spe- repair parts list in this RPSTL cialized Repair . If the item is authorized to you Act (SRA)) by the 3d position code of the SMR  code,   but the source MD-(Made at Depot) code indicates it is made at a higher level,  order the item from the higher level of main- tenance. AO-(Assembled by Items with these codes are not UM/A VUM Level) to be requested/requisitioned individually. The parts that AF-(Assembled by make up the assembled item IDS/’AVIM Level) must be requisitioned or fabri- AH-(Assembled by cated and assembled at the IGAH-(Assembled level of maintenance indicated by IGS Category by the source code If the 3d AL-(Assen7bledby position code of the SMR code SRA) authorizes you to replace the item,  but the source code indi- AD-(Assembled by cates the item is assembled at Depot) a higher level,  order the item from the higher level of main- tenance. XA - Do not requisition an "XA"-coded item Order its  next higher assembly. (Refer to the NOTE,   following ) XB - If an "XB" item is not available from salvage,   order it using the FSCM 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 and part number given,  if no NSN is available. NOTE: Cannibalization or controlled exchange,  when authorized,  may be used as 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- Intermediate Direct support or aviation intermediate is the lowest level that can do complete repair of the item. H- Intermediate General support is the lowest level that can do complete repair of the item. 2