Generator   Set,   volume   2.   These   procedures   provide detailed   engine   and   interference   removal   instructions. These  instructions  should  be  strictly  followed  due  to  the vast   differences   in   removal   procedures   between   a propulsion   GTE   and   an   SSGTG. You   must   use   the   same   planning   skills   and engineering  practices  in  a  GTG  engine  changeout  as  you use   in   an   LM2500   GTE   changeout.   The   same   strict application   of   safety   precautions   and   following   of technical  manual  procedures  apply  to  every  GTG  engine changeout. COOPERATION Ship’s  readiness  is  the  common  purpose  in  the changeout    evolution. All   personnel   involved   should share  a  common  commitment  in  achieving  that  purpose. A  willingness  by  each  individual  to  submerge  his  or  her personal   interest   in   favor   of   getting   the   job   done   is   a necessary  prerequisite  to  cooperation.  You  may  have  to adjust  working  hours  and  watch-standing  duties  to  meet changeout   schedule   requirements.   Personnel   may   be assigned   to   duties   they   do   not   want   to   perform. Emphasize   each   individual’s   importance,   willingness, and   contribution   to   the   evolution.   Engine   changeout   is an  opportunist  y  to  display  your  professional  abilities  as a  leader  and  technician MAINTENANCE   TIPS As  a  GS  supervisor  you  will  be  responsible  for  the proper  completion  of  most  maintenance  procedures. This   section   will   cover   some   maintenance   tips   that   can help  you  to  understand  the  critical  relationship  between maintenance  performance  and  the  proper  operation  of the  LM2500.  Remember,  the  contents  of  this  section  are FOR   TRAINING   PURPOSES   ONLY   and  should  in no  way  replace  the  use  of  the  PMS  or  the  manufacturer’s maintenance    procedures. PLA   RIGGING If  the  PLA  is  replaced  for  whatever  cause,  the  PLA rig   check   (mechanical   and   electrical)   must   be accomplished.  If  the  main  fuel  control  (MFC)  rig  pin does   not   fit   properly   (too   loose,   too   tight,   or   can’t   be fully  inserted),  re-rig  the  PLA.  Always  comply  with  the PLA  electrical  rig  check  after  you  are  assured  that  the throttle  command  voltages  are  properly  set  (idle  and  full throttle). Mechanical The   key   to   a   successful   mechanical   rigging   is   a proper   alignment. Remember,   although   the   PLA actuator   arm   is   mechanically   linked   to   the   MFC   lever arm,   the   PLA   is   electrically   driven.   The   slightest mechanical   restriction   (binding)   may   cause   incorrect PLA   movement   during   engine   operation.   PLA movement   is   most   sensitive   to   a   restriction   when   in either   engine   speed   or   torque,   and/or   shaft   torque limiting  condition.  If  a  possible  restriction  is  suspected, advance   and   retard   the   PLA   electrically   and   check   for any   hesitation   or   jerking   during   travel.   If   hesitation exists,   there   may   be   a   mechanical   restriction. Electrical The  normal  process  for  this  rigging  will  be  checking dc  voltages  at  idle  and  full  throttle  positions.  However, the  moment  the  throttle  is  moved  out  of  idle,  indicated torque  will  go  to  midrange  and  oscillate.  For  example, on   the   DD-963/DDG-993   class   ships,   if   mid-torque oscillations   are   accompanied   by   an   overtorque indication  and  a  PLA  failure  indication,  then  another problem  exists. Why?  When  the  PLA  is  at  idle,  there  is  a  PT5.4  bias that   assures   PT5.4  is  greater  than  PT2 for   engine   start purposes.  During  PLA  electrical  rigging,  the  bias  drops out  when  the  throttle  is  advanced. If  PT5.4  is  several  tenths  of  a  pound  less  than  PT2, the   torque   computer   goes   berserk.   But,   PLA   rigging may   be   continued   by   pressing   the   BATTLE OVERRIDE   button. However,  suppose  you  have  just  been  informed  that the   PT5.4  transducer   requires   calibration   When   the torque   goes   berserk   as   described,   immediately   dial   up P T5.4  and   PT2 on   the   respective   DDIs.   PT5.4  will   be lower   than   PT2,   thus   requiring   the   activation   of BATTLE   OVERRIDE   to   continue.   This   lower   reading tells  you  the  PT5.4  transducer   requires   calibration. VSV   FEEDBACK   CABLE   RIGGING Why  is  it  accomplished? Why   is   it   important? VSV  feedback  cable  rigging  is  necessary  because we  are  “timing”  a  pilot  valve  inside  the  MFC  so  the correct  vane  angle  is  obtained  for  a  given  CIT/gas generator  speed  day.  Actually,  we  are  assuring  that  the pilot  valve  is  timed  to  close  off  high  pressure  fuel  flow to   both   the   ROD   END   and   the   HEAD   END   pressure 2-32