F-3. EXPLANATION OF COLUMNS (SECTIONS II AND III) (continued).
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 Commercial and Government Entity Code
(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.
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 coded "XA."
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:
Crew or Operator maintenance done within Unit maintenance or Aviation Unit
Unit or Aviation Unit level 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