conditions. This information will aid you in interpretingwhat you see by evaluating the color of the area orcomponent. Color photographs taken through theborescope are an effective method to record the resultsof an inspection.It is difficult to make accurate color interpretation.Table 2-3 is only an aid. The only color indication thatmight give immediate cause for concern is aluminumoxide splatter in the hot section of the engine. Othercolorations are normal and do not limit the service lifeof the engine.WATER WASHINGWater washing an engine as a prerequisite toborescope inspections is the best way to achieve anaccurate evaluation of an engine’s condition. Dirt andsoft carbon deposits may obscure small cracks andpitting that could be missed if the engine were dirty. Formore information on borescoping procedures, youshould consult the technical manual for I n t e r n a lInspection and Evaluation of Marine Gas TurbineE n g i n e s( M o d e lL M 2 5 0 0 ) ,N A V S E AS9234-D1-GTP-010.REPORTING INSPECTION RESULTSUnless a discrepancy is found, you do not have toenter routine borescope inspections in the Marine GasTurbine Engine Service Record (MGTESR). However,if the inspection was conducted as a troubleshootingprocedure due to an engine malfunction or was orderedby a higher authority, you must log the inspection andnote the findings.You must evaluate and report allmajor damage or exceeded service limits to NAVSEA.If the damage or wear is extensive, the engine must bereplaced.Further information on the MGTESR isprovided in chapter 1 of this TRAMAN and NavalShips’ Technical Manual (NSTM), chapter 234, “MarineGas Turbines.”TROUBLESHOOTINGAs a GS supervisor, you will find that successfultroubleshooting is a rewarding experience. Proper useof the manufacturer’s technical manual will enhanceyour professional abilities and result in getting the jobdone right the first time. This section discusses the useof the troubleshooting sections of the LM2500 GTEtechnical manual.TROUBLESHOOTING TECHNIQUESTroubleshooting is a systematic analysis ofsymptoms that indicate an equipment malfunction.These symptoms usually appear as deviations from thenormal parameters.You must be able to recognizenormal operating conditions to recognize abnormaloperation. If you have a thorough knowledge ofequipment systems and use logical reasoning, you willbe able to solve most troubleshooting problems withlittle difficulty.The basic methods used duringmechanical and electrical/electronic troubleshootingare as follows:Be sure you know the normal operatingconditions (be able to recognize a problem).Find out everything about the nature of themalfunction. Write down all the symptoms andsee 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 alignmentLM2500 TROUBLE ISOLATIONThe trouble isolation section (volume 2) of theLM2500 technical manual contains three chapters withtroubleshooting information that will aid you inisolating faults and malfunctions in the LM2500 GTEand its ancillary equipment. The manual presentstroubleshooting procedures in fault logic diagrams,fictional dependency diagrams (FDDs), and signalflow diagrams.Fault Logic DiagramsThese diagrams are based on a fault indicationobserved during troubleshooting. The diagramscomprise a branching series of questions pertaining tofault isolation. Each question pertains to furtherobservation or measurement, and results in a yes or no2-26
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