EXPLANATION OF COLUMNS (SECTIONS II AND III) (continued).
Cannibalization or controlled exchange, when authorized, may be used as a source
of supply for items with the preceding source codes, except for those source-
XA - DO NOT requisition an XA-coded item. Order its next higher assembly.
XB - If an XB item is not available from salvage, order it using the CAGEC and part number given.
XC - Installation drawing, diagram, instruction sheet, or field service drawing that is identified by manufacturer's part
XD - Item is not stocked. Order an XD-coded item through normal supply channels using the CAGEC and part number
given if no NSN is available.
(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
(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:
Crew or operator maintenance done within Unit maintenance or Aviation Unit
Organizational maintenance or Aviation Unit can remove, replace, and use the item.
Direct support or aviation intermediate level can remove, replace, and use the item.
General support level can remove, replace, and use the item.
Specialized repair activity (SRA) can remove, replace, and use the item.
Depot level can remove, replace, and use the item.
If authorized by the maintenance allocation chart (MAC) and SMR codes, some
limited repair may be done on an item at a lower level of maintenance.
(b) The maintenance code entered in the fourth position tells whether 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). This position will contain one of the following maintenance codes: