transducer  excitation  and  output  coils.  The  rotating electronics   cylinder   rectifies   the   rotary   transformer excitation  to  24  V  dc  for  powering  the  hub-mounted transducer   and   receives   the   transducer   output.   The rotating  electronics  cylinder  is  attached  to  the  prairie  air tube  extension  at  the  end  of  the  OD  box.  The  cylinder electronically  regulates  the  transducer  output  to^- 3  kHz for   the   rotary   transformer.   For   a   more   detailed description   of   this   system’s   operation,   consult   the DDG-51   propulsion   plant   manual   or   the   DDG-51   CPP system   technical   manual. Emergency    Operation P   for   the   online   strainers   and If   the   electronic   pitch   control   system   becomes inoperative,  you  must  instruct  your  personnel  to  shift  to manual   control   at   the   OD   box.   Manual   operation   is accomplished  by  shifting  the  two  changeover  valve levers   on   the   manifold   block   assembly   from   AUTO   to MANUAL.  The  propeller  will  remain  at  the  pitch  set initiated  at  the  time  of  the  change.  You  can  change  the pitch  by  operating  the  control  valve  lever  and  observing the   local   pitch   indicator. Once   the   problem   with   the   electronic   controls   has been   corrected,   shift   back   to   automatic   operation. Before  initiating  the  change  from  MANUAL  to  AUTO, be   sure   the   pitch   command   signal   from   the   controlling remote  station  matches  the  actual  pitch  setting  at  the time  the  mode  change  (manual  to  auto)  is  initiated.  Shift the  two  changeover  levers  simultaneously  to  the  AUTO position.  If  the  command  signal  and  actual  pitch settings   do   not   match,   the   pitch   will   automatically change  to  the  commanded  pitch  upon  completion  of  the mode  change. a . If  the  local  manual  mode  is  inoperative,  shift  the changeover   valves   to   the   OFF   position,   secure   the hydraulic   oil   power   module   (HOPM),   and   set emergency   pitch   according   to   engineering   operational b. sequence   system   (EOSS)   procedures. NOTE When   operating   in   the   emergency   ahead   mode, the   OD   box   temperature   must   be   monitored continuously.  You  may  have  to  apply  cooling  water to  the  OD  box  housing  to  maintain  the  temperature below   160°F.   Remember,   the   most   effective   and preferred   method   to   maintain   OD   box   temperatures is  the  use  of  prairie  air. CRP/CPP   SYSTEM   INSPECTIONS The  following  is  a  list  of  routine  checks  and  services that  should  be  made  to  the  CRP/CPP  system  while underway: 1.  Hourly a. b. c. d. Check   the   OD   box   temperature,   160ºF maximum   (150°F   DDG-51   class). Check   the   hydraulic   system   oil   pressures; ensure   all   comply   with   EOSS. Check  the  prairie  air  rotoseal  for  leaks. Check   the  D falters. 2.   Each   watch a.  Check  the  hydraulic  oil  level  in  the  sump  and head   tank. b.  Inspect  the  hydraulic  system  for  leaks  and vibration. 3.   Before   entering   port   or   any   restricted maneuvering   situation a.   Verify   the   control   system   response   by decreasing   pitch   slightly   and   noting response. b.   Verify   the   pump   (attached   or   electric) operation   depending   on   ship   class. 4.   When   the   system   is   secured Check  the  oil  level  in  the  head  tank.  If  the head   tank   oil   level   is   low,   replenish   oil   as necessary   by   operating   the   system   until   the oil  level  returns  to  normal. Inspect   the   oil   for   water   contamination periodically. CRP/CPP  TROUBLESHOOTING  AND MAINTENANCE Even  though  the  CRP/CPP  systems  installed  on  a gas  turbine-powered  ship  use  the  same  types  of  pumps and  fluids  as  the  MRG  LO  system,  they  are  much  more sophisticated. Paying   close   attention   to   system operating   pressures   is   your   most   important   step   in successfully  troubleshooting  any  problem  and  making the  appropriate  repairs.  The  following  paragraphs  will describe  some  of  the  common  problems  associated  with system  pressure  and  the  methods  you  can  use  to  identify the  component  or  components  that  might  be  causing  the 3-16