TM   10-7360-206-23P T.O.   35E4-172-5-4 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 requirements of AR 750–1. (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 C    — O   — F — H    — L — D    — Application/Explanation Crew or operator maintenance done within organizational or aviation unit maintenance. Organizational  or  aviation  unit  category  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  can  remove,  replace,  and  use  the  item. 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 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 O    — F — H    — L — D    — Z — B    — Application/Explanation Organizational or aviation unit is the lowest level that can do complete repair of the item. Direct support or aviation intermediate is the lowest level that can do complete repair of the item. General Support is the lowest level that can do complete repair of the item. Specialized repair activity is the lowest level that can do complete repair of the item. Depot is the lowest level that can do complete repair of the item. Nonreparable. No repair is authorized. 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