TM 10-8400-201-23 1-8.  SOURCE, MAINTENANCE AND RECOVERABILITY (SMR) CODES - Continued CODE EXPLANATION AL Item to be assembled at the SRA. AD Item to be assembled at depot maintenance category. XA Item is not procured or stocked, because the requirements for the item will result in the replacement of the next higher assembly. XB Item is not procured or stocked. If not available through salvage, requisition. XC Installation  drawing,  diagram,  instruction  sheet,  field  service  drawing,  that  is  identified  by  manufacturer's  part number. XD A low mortality support item that is not stocked. When required, items will be requested and provided through normal supply channels. b. Maintenance  Use  Code  (third  position).    This  position  will  indicate  the  lowest  maintenance  category  authorized  to remove, replace, and use the support item.  The maintenance use entered in the third position will indicate one of the following categories of maintenance. CODE EXPLANATION O Support item is removed, replaced, and used at organizational (or AVUM/ON-SITE) category of maintenance. F Support Item is removed, replaced, and used at direct support (or AVIM/OFF-SITE) category of maintenance. H Support item is removed, replaced, and used at general support (or AVIM/OFF-SITE) category of maintenance. D Support item is removed, replaced, and used only at depot. c. Maintenance Repair Code (fourth position).  This position will indicate whether or not the item is to be repaired, and will  identify  the  lowest  category  with  the  capability  to  perform  complete  repair.    This  complete  repair  excludes overhaul  or  rebuild  functions  prescribed  by  Depot  Maintenance  Work  Requirements(DMWR),  but  encompasses performing  all  other  authorized  maintenance  functions,  services  (inspect,  test,  service  adjust,  align,  calibrate),  or actions (welding, grinding, riveting, straightening, facing, remachining, or resurfacing) required to restore an item to serviceable  condition  by  correcting  specific  failures  or  damage.    Complete  repair  coding  does  not  preclude  repair which may be authorized to a lower category of maintenance.  The MRC entered in the fourth position will indicate one of the following: CODE APPLICATION/EXPLANATION O The unit (AVUM/ON-SITE) category of maintenance is the lowest level capable of complete repair. F The IDS (AVIM/OFF-SITE) category of maintenance is the lowest level capable of complete repair. H The IGS (AVIM/OFF-SITE) category of maintenance is the lowest level capable of complete repair. L The SRA is the lowest activity capable of complete repair. Change 5  1-22