TM  5-4930-226-12&P D-2. Use of the Maintenance Allocation Chart, Section  II a. The  MAC  assigns  maintenance  functions  bas- ed on the following considerations: (1) Skills  available. (2) Work  time  required. (3) Tools and test equipment required and/or available. b. If  a  lower  level  of  maintenance  identified  in  col- umn (4) of the MAC cannot perform all tasks of a single  maintenance  function  (e.g.,  test,  repair),  then the  higher  level  that  can  perform  other  tasks  of  that function  is  also  indicated. c. Higher  maintenance  levels  are  automatically authorized  to  perform  maintenance  functions  assign- ed  to  a  lower  maintenance  level. d. Higher  maintenance  levels  will  perform  the maintenance functions of lower maintenance levels when  required  or  directed  by  the  Commander  who  has authority to direct such tasking. e. Assignment of a maintenance function in the MAC does not carry automatic authorization to carry the  related  spare  or  repair  parts  in  stock.  Information to requisition or secure parts will be as specified in the associated  RPSTL. f. Normally,  there  will  be  no  deviation  from  the assigned  level  of  maintenance.  However,  in  cases  of operational  necessity,  maintenance  functions  assign- ed a higher level may, at the request of the lower level, be  assigned  to  the  lower  level  on  a  one-time  basis,  if specifically  authorized  by  the  maintenance  officer  of the higher level to which the function is assigned. In such a case, the special tools, equipment, etc., required by the lower level to perform this function will be fur- nished  by  the  higher  level  assigned  the  function.  Also, transfer of a function to a lower level does not relieve the  higher  level  of  responsibility  for  the  function,  so the  higher  level  will  provide  technical  supervision  and inspection of the function being performed at the lower  level. D-3.  Maintenance  Functions Maintenance functions will be limited to and defin- ed  as  follows: a. Inspect.  Two  levels  of  inspect  are  covered  in  the MAC. (1) When prescribed at the C or O element of Unit  Maintenance  level,  inspect  means  to  determine serviceability by comparing an item’s physical, mechanical, and/or electrical characteristics with established  standards  through  examination  (i.e.,  by sight,  sound,  or  feel).  These  inspections  are  included in  preventive  maintenance  (PM)  checks  and  services, such as PMCS, PMD. D-2 Change 4 (2) When prescribed at the intermediate (F) or Depot  (D)  maintenance  level,  inspect  refers  to  an  in- itial inspection which is conducted prior to scheduling any  repair  on  repairable  items  evacuated  to  this  level. This  inspection  is  made  to  determine  whether  au  item qualifies  for  repair  or  discard. b. Test. To verify serviceability and detect inci- pient failure by measuring the mechanical or electrical characteristics  of  an  item  and  comparing  those  char- acteristics  with  prescribed  standards. c. Service.  Operations  required  periodically  to keep  an  item  in  proper  operating  condition,  i.e.,  to clean  (includes  decontaminate),  to  preserve,  to  drain, or to replenish fuel, lubricants, hydraulic fluids, or compressed  air  supplies. d. Adjust.  To  maintain  within  prescribed  limits, by  bringing  into  proper  or  exact  position,  or  by  setting the  operating  characteristics  to  the  specified parameters. e. Align. To adjust specified variable elements of an  item  to  bring  about  optimum  or  desired performance. f. Calibrate.  To  determine  and  cause  corrections to  be  made  or  to  be  adjusted  on  instruments  or  test measuring  and  diagnostic  equipment  used  in  precision measurement.  Consists  of  comparison  of  two  in- struments, one of which is a certified standard of known  accuracy,  to  detect  and  adjust  any  discrepan- cy in the accuracy of the instrument being compared. g. Install. The act of emplacing, seating, or fixing into  position  an  item,  part,  or  module  (component  or assembly)  in  a  manner  to  allow  the  proper  functioning of  an  equipment  or  system. h. Replace.  The  act  of  substituting  a  serviceable like  type  part,  a  subassembly,  or  modeule  (component or  assembly)  for  an  unserviceable  counterpart. i. Repair.  The  application  of  maintenance  services (inspect,  test,  service,  adjust,  align,  calibrate,  or replace)  or  other  maintenance  actions  (welding,  grind- ing, riveting, straightening, facing, remachining, or resurfacing)  to  restore  serviceability  to  an  item  by  cor- recting specific damage, f auk, malfunction, or failure in a part, subassembly, module (component or assembly),  end  item,  or  system. j. Ouerhaul. That  maintenance  effort  (service/ac- tion)  necessary  to  restore  an  item  to  a  completely  ser- viceable operational condition as prescribed by maintenance  standards  in  appropriate  technical publications  (i.e.,  DMWR).  Overhaul  is  normally  the highest  degree  of  maintenance  performed  by  the Army. Overhaul does not normally return an item to a  like  new  condition.