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
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