TM 9-2805-259-24P TO  38G2-89-54 SL-403524C NOTE Cannibalization or controlled exchange, when authorized, maybe 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  require- ments of AR 750-1. (2)  Maintenance  Code.  Maintenance  codes  tells  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 indi- cate authorization to one of the following levels of maintenance. Code Application/Explanation C - Crew or operator maintenance done with unit or aviation unit maintenance. O - Unit 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 re- paired 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 mainte- nance, 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 or (aviation unit) is the lowest level that can do complete repair of the item. F- Direct support or aviation intermediate is the lowest level that can do complete repair of the item. H - General Support is the lowest level that can do complete repair of the item. L - Specialized repair activity is the lowest level that can do complete repair of the item. D - Depot is the lowest level that can do complete repair of the item. Z - Nonreparable. No repair is authorized. B - No repair is authorized. (No parts or special tools are authorized for the maintenance of a “B" coded Item). However, the item may be reconditioned by adjusting, lubricating, etc., at the user level. (3) Recoverability Code. Recoverability codes are assigned to items to indicate the disposition action on unserviceable items. The recoverability code is entered in the fifth position of the SMR Code as follows: 3