TM 55-1560-307-13&P APPENDIX B MAINTENANCE ALLOCATION CHART Section I.  INTRODUCTION B-1.  MAINTENANCE ALLOCATION CHART. a.  This Maintenance Allocation Chart (MAC) assigns maintenance   functions   in   accordance   with   the   Three Levels of Maintenance concept for Army Aviation.  These maintenance levels (categories) Aviation Unit Maintenance (AVUM), Aviation Intermediate Maintenance (AVIM), and Depot Maintenance are depicted on the MAC as: AVUM,  which  corresponds  to  an  0  Code  in  the  Repair Parts and Special Tools List (RPSTL) AVIM,  which  corresponds  to  an  F  Code  in  the  Repair Parts   and   Special   Tools   List   (RPSTL)   DEPOT,   which corresponds to a D Code in the Repair Parts and Special Tools List (RPSTL) b.    The  maintenance  to  be  performed  below  depot and in the field is described as follows: (1)        AVUM    activities    will    be    staffed    and equipped to perform high frequency "On-Aircraft" maintenance   tasks   required   to   retain   or   return   aircraft systems  to  a  serviceable  condition.    The  maintenance capability of the AVUM will be governed by the MAC and limited  by  the  amount  and  complexity  of  ground  support equipment (GSE), facilities required, authorized manning strength,   and   critical   skills   available.      The   range   and quantity of authorized spare modules/components will be consistent  with  the  mobility  requirements  dictated  by  the air mobility concept.  (Assignments of maintenance tasks to divisional company size aviation units will consider the overall    maintenance    capability    of    the    division,    the requirement     to     conserve     personnel     and     equipment resources, and air mobility requirements.) (a)  Company size aviation units.  Perform those     tasks     which     consist     primarily     of     preventive maintenance   and   maintenance   repair   and   replacement functions associated with sustaining a high level of aircraft operational readiness.  Perform maintenance inspections and   servicing   to   include   preflight,   daily,   intermediate, periodic (or phased), and special inspections as authorized  by  the  MAC  or  higher  headquarters.    Identify the     cause     of     equipment/system     malfunctions     using applicable  technical  manual  troubleshooting  instructions, built-in test equipment (BITE), installed aircraft instruments,     or     test,     measurement,     and     diagnostic equipment (TMDE). Replace worn or damaged modules/components that do not require complex adjustments   or   system   alinement   and   which   can   be removed/installed  with  available  skills,  tools,  and  ground support  equipment.    Perform  operational  and  continuity checks  and  make  minor  repairs  to  the  electrical  system. Inspect,   service   and   make   operational,   capacity,   and pressure checks to hydraulic systems.  Perform servicing, functional  adjustments,  and  minor  repair/replacement  to the    flight    control,    propulsion,    power    train,    and    fuel systems.      Accomplish   air   frame   repair   that   does   not require extensive disassembly, jigging, or alinement.  The manufacture  of  air  frame  parts  will  be  limited  to  those items  which  can  be  fabricated  with  tools  and  equipment found in current air mobile tool and shop sets.  Evacuate unserviceable modules/components and end items beyond  the  repair  capability  of  AVUM  to  the  supporting AVIM. B-1