PM group. When DTO parts are received, they must be  placed  in  the  cube  that  corresponds  to  the  PM group of the equipment requiring the parts. Technical  Librarian Technical  librarians  are  responsible  for  the prepacked  library  consisting  of  operational, maintenance,  and  part’s  manuals.  They  establish  and enforce  check-out  procedures  for  manuals  and  initiate parts  requisitions  on  NAVSUP  Form  1250s.  The  task of researching and preparing the 1250s is normally handled  by  the  technical  librarian  to  free  the  floor mechanics  to  perform  maintenance  functions. MAINTENANCE  LEVELS The CESE Maintenance System of the NCF and SOU  has  three  categories  of  maintenance.  These three  categories  are  (1)  organizational,  (2)  inter- mediate,  and  (3)  depot. Organizational Maintenance Organizational maintenance is divided into two classifications:  operator  maintenance  and  preventive maintenance. Operator maintenance is that which every  operator  is  required  to  perform  to  maintain  the equipment  in  a  clean,  safe,  and  serviceable  condition. It  includes  the  daily  inspections,  lubrications,  and adjustments  necessary  to  ensure  early  detection  of equipment  malfunctions. The   prime   objective   of preventive  maintenance  is  to  maximize  equipment availability  and  minimize  repair  costs.  Preventive maintenance  consists  of  safety  and  serviceability inspections,    lubrication,   minor   services,   and adjustments beyond those in operator maintenance. Operators  should  participate  in  this  work  unless specifically   directed   otherwise. Intermediate Maintenance Intermediate   maintenance   provides   a   higher degree  of  skill  than  organizational  maintenance.  The extent of intermediate maintenance is the removal, replacement,   repair,  alteration,  calibration,  modi- fication, and the rebuild and overhaul of individual assemblies,  subassemblies,  and  components.  Only essential  repairs  are  accomplished  to  ensure  safe  and serviceable   equipment.   Prior  approval  is  required  on equipment requiring extensive repairs or numerous assemblies  that  are  rebuilt. Depot Maintenance Depot  maintenance  is  performed  on  equipment requiring   major   overhaul   or   comprehensive restoration that returns CESE to a like-new condition. Most  NCF  depot  maintenance  is  performed  by  the Construction Equipment Department (CED) at both Port  Hueneme,  California,  and  Gulfport,  Mississippi. Maintenance Scheduling The   standard   interval   between   PM   service inspections for NCF equipment is 40 working days. This interval is established by grouping all assigned equipment  into  40  separate  PM  groups  (fig.  1-19). The equipment is distributed evenly throughout the PM  groups,  so  only  a  minimum  number  of  similar types of equipment are out of service at the same time. For  reserve  units,  the  standard  PM  interval  is  90 calendar days, and the equipment is assigned to one of six  PM  groups. The  maintenance  supervisor  is  responsible  for determining  when  the  PM  interval  for  an  item  of equipment should be reduced. The time interval can be reduced by assigning specific items of equipment to  more  than  one  group  or  by  reducing  the  total number of groups. The interval between PM service inspections  for  active  CESE  should  never  extend beyond   the   maintenance   scheduling   standards. Continuity  of  the  PM  schedule  is  maintained  by transferring the schedule from a relieved unit to the relieving  unit. TYPE    A    (01)    INSPECTION.—     Type    A inspections  are  given  at  intervals  of  40  working  days, using  the  appropriate  PM  Service  and  Inspection Guide  set  forth  in  the  COMSECOND/COMTHIRD- NCBINST  11200.1  Series.  Type  A  inspections  are given at 90 calendar days for the reserve NCBs. Type A inspections are performed on each PM scheduled date   until   the   vehicle   qualifies   for   a   Type   B inspection. TYPE B (02) INSPECTION.— To prevent a unit of CESE from being over inspected or over serviced, you  should  perform  Type  B  inspections  only  when  the mileage and hours equal that recommended by the manufacturer. TYPE C (03) INSPECTION.—  Type C annual safety   inspection   (SI)(ASI)   is   directed   by   COM- SECOND/COMTHIRDNCB   representatives.   The maintenance  supervisor  is  required  to  schedule 50 percent of CESE on site to receive a Type C safety 1-23