MODERN BURNER UNIT (MBU)
REPAIR PARTS AND SPECIAL TOOLS LIST (RPSTL)
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 750-1.
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:
Third Position. The maintenance code entered in the third position tells you the lowest maintenance level
authorized to remove, replace, and use the support 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/AVUM maintenance.
Unit level/AVUM maintenance can remove, replace, and use the item.
Direct support/AVIM maintenance can remove, replace, and use the item.
General support maintenance can remove, replace, and use the item.
Specialized repair activity can remove, replace, and use the item.
Depot level can remove, replace, and use the item.
Fourth Position. 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
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.)