As a watch stander, you can readily identify poor
3. Before leaving the intake plenum or inlet air duct
engine performance by a noticeable increase in the TIT,
area, inspect for foreign objects. Account for all tools,
hard starting, and poor engine response when electrical
parts, materials, and personnel.
loads are added. The loss of the engine's serviceable life
is normally caused by salt or sand erosion of the engine's
CAUTION
casing and blades.
Objects left in the inlet area can cause GTE
Water Washing
damage.
Whenever you are preparing to perform mainte-
You can accomplish internal cleaning of your
nance within any part of the engine, always follow the
engine by the procedure referred to as water washing.
authorized procedures and keep your attention focused
The water washing procedures for all the GTEs we have
on the job at hand.
discussed in this chapter are similar. For the specific
water washing procedures for your particular GTE, refer
to the appropriate PMS procedures or manufacturer's
ROUTINE GTE MAINTENANCE
technical manuals for your ship. You will need this
As a GSM, you will be direct] y involved in the
information to make decisions concerning several
maintenance and upkeep of your ship's prime mover.
different factors, such as hours of operation, sea state,
Most of the routine maintenance procedures you will be
and so forth; the cleaning medium you should use, such
required to perform will fall in the general areas of
as water or solvent solution; and the maintenance
cleaning (and lubricating), tests and inspections,
borescoping, and removal and replacement of some of
All GTEs installed on gas turbine-powered ships
the components. Let's first take a general look at these
have spray nozzles located on the engine's air inlet
areas. We will then discuss your general maintenance
assembly (bellmouth) or in the air inlet plenum. These
responsibilities in terms of specific systems and
nozzles are aimed directly into the airstream of the
components.
compressor section.
CLEANING
Among the different GTEs, however, the design or
method by which the wash liquid is delivered to the
One of the most frequent and critical maintenance
engine's intake, as well as the liquid itself, may be
procedures you will ever perform is cleaning. The
different. For example, let's look at the differences
quality of attention you give to your engine's
between the water wash system installed on the Allison
cleanliness, both inside and out, can either enhance or
and the one installed on the Garrett.
downgrade its performance. Let's take a brief look at
ALLISON AND GARRETT. Even though the
cleaning in terms of your responsibilities for both
water wash systems in both the Allison and Garrett are
external and internal cleaning of the engine.
permanently piped, the wash solution is pressurized
External Cleaning
differently. In the Allison, the ship's low-pressure air
system provides the required pressure. In the Garrett, a
External cleaning of the engine and its enclosure is
booster pump supplies the wash solution at the required
not only a good engineering practice but also an
pressure.
important way to help you, the watch stander, identify
SUNSTRAND. The Sunstrand water wash system
leak locations and possible component failure.
also uses a booster pump, but only to deliver distilled
Improperly performed external cleaning can lead to
water. When the Sunstrand requires a detergent
potential hazards to both equipment and personnel.
cleaning, the detergent (PD-680 type II) must be
delivered to the compressor inlet through a handheld
Internal Cleaning
spray nozzle.
WATER WASH OPERATION. In all cases, the
The requirements for internal cleaning are also
extremely important. The lack of cleaning or improperly
GTE is motored as the water or wash solution enters the
engine's inlet. There, the wash solution or water breaks
performed cleaning will result in poor engine
performance and the reduction in the engine's
up oil, dirt, and salt deposits. The used solution or water
serviceable life.
is then carried downstream to the exhaust plenum. After
