conditions.  This  information  will  aid  you  in  interpreting what  you  see  by  evaluating  the  color  of  the  area  or component.   Color   photographs   taken   through   the borescope  are  an  effective  method  to  record  the  results of  an  inspection. It   is   difficult   to   make   accurate   color   interpretation. Table  2-3  is  only  an  aid.  The  only  color  indication  that might  give  immediate  cause  for  concern  is  aluminum oxide  splatter  in  the  hot  section  of  the  engine.  Other colorations  are  normal  and  do  not  limit  the  service  life of  the  engine. WATER   WASHING Water   washing   an   engine   as   a   prerequisite   to borescope   inspections   is   the   best   way   to   achieve   an accurate   evaluation   of   an   engine’s   condition.   Dirt   and soft  carbon  deposits  may  obscure  small  cracks  and pitting  that  could  be  missed  if  the  engine  were  dirty.  For more   information   on   borescoping   procedures,   you should  consult  the  technical  manual  for  I n t e r n a l Inspection   and   Evaluation   of   Marine   Gas   Turbine E n g i n e s ( M o d e l L M 2 5 0 0 ) , N A V S E A S9234-D1-GTP-010. REPORTING  INSPECTION  RESULTS Unless  a  discrepancy  is  found,  you  do  not  have  to enter   routine   borescope   inspections   in   the   Marine   Gas Turbine  Engine  Service  Record  (MGTESR).  However, if   the   inspection   was   conducted   as   a   troubleshooting procedure  due  to  an  engine  malfunction  or  was  ordered by  a  higher  authority,  you  must  log  the  inspection  and note   the   findings. You  must  evaluate  and  report  all major   damage   or   exceeded   service   limits   to   NAVSEA. If  the  damage  or  wear  is  extensive,  the  engine  must  be replaced. Further   information   on   the   MGTESR   is provided   in   chapter   1   of   this   TRAMAN   and   Naval Ships’  Technical  Manual  (NSTM),  chapter   234,   “Marine Gas  Turbines.” TROUBLESHOOTING As   a   GS   supervisor,   you   will   find   that   successful troubleshooting  is  a  rewarding  experience.  Proper  use of   the   manufacturer’s   technical   manual   will   enhance your   professional   abilities   and   result   in   getting   the   job done  right  the  first  time.  This  section  discusses  the  use of   the   troubleshooting   sections   of   the   LM2500   GTE technical   manual. TROUBLESHOOTING    TECHNIQUES Troubleshooting   is   a   systematic   analysis   of symptoms   that   indicate   an   equipment   malfunction. These   symptoms   usually   appear   as   deviations   from   the normal    parameters. You   must   be   able   to   recognize normal   operating   conditions   to   recognize   abnormal operation.   If   you   have   a   thorough   knowledge   of equipment   systems   and   use   logical   reasoning,   you   will be   able   to   solve   most   troubleshooting   problems   with little    difficulty. The   basic   methods   used   during mechanical   and   electrical/electronic   troubleshooting are  as  follows: Be   sure   you   know   the   normal   operating conditions  (be  able  to  recognize  a  problem). Find   out   everything   about   the   nature   of   the malfunction.   Write   down   all   the   symptoms   and see  if  they  follow  an  identifiable  pattern. Check   the   obvious: —Blown   fuses —Tripped  circuit  breakers —Faulty   alarms —Loose   connectors   and   cannon   plugs —Switches   in   the   wrong   position —Burned-out   lamps —Physical    damages —Last  PMS  or  maintenance  procedure  performed —System    alignment LM2500   TROUBLE   ISOLATION The   trouble   isolation   section   (volume   2)   of   the LM2500   technical   manual   contains   three   chapters   with troubleshooting   information   that   will   aid   you   in isolating   faults   and   malfunctions   in   the   LM2500   GTE and   its   ancillary   equipment.   The   manual   presents troubleshooting   procedures   in   fault   logic   diagrams, fictional   dependency   diagrams   (FDDs),   and   signal flow   diagrams. Fault   Logic   Diagrams These  diagrams  are  based  on  a  fault  indication observed   during   troubleshooting.   The   diagrams comprise   a   branching   series   of   questions   pertaining   to fault   isolation.   Each   question   pertains   to   further observation  or  measurement,  and  results  in  a  yes  or  no 2-26