Your first step is to narrow down the possible
Ship's and MER Nonvital Air Systems
sources of the problem by isolating each of the three
These two subsystems, the ship's nonvital air
remaining SSAS subsystems, one at a time. The first
system and the MER nonvital air system, are used for
subsystem you should check is the MER vital air,
all of the same types of service. Both systems are
Identify the operating equipment supplied by the MER
designed to service all nonvital equipment, such as the
vital air subsystem. If practical, secure these equipment
pilothouse window washer, tool outlets, and several
units. Once you have isolated the MER header and air
other nonvital equipment units.
pressure is restored, then you have narrowed down the
location of the leak to this area. If air pressure does not
The number of compressors needed to support these
restore, however, then you will need help from outside
four basic subsystems will vary according to the class
the MER. Before proceeding, you must check with all
of ship. It does not matter, however, how many
other divisions who receive service from the MER vital
air system and have them inspect their equipment and
can be cross-connected or isolated from each other with
piping until the problem is isolated.
the proper valve confikguration. An occasion may arise
when none of the LPACs may be available. If this
occurs, then the SSAS can be cross-connected with the
Maintenance
HP air system (HPAS). For this configuration, you must
make sure all nonvital systems are isolated. Isolating the
Upkeep of the overall SSAS will consist of two
nonvital system will help you make certain the depletion
main areas: (1) valve maintenance and preservation and
of the HPAS is minimal.
(2) maintenance of the compressors and their associated
Tests and Inspections
maintaining and preserving the reducing station
assemblies and all the manual valves. Maintenance of
Tests and inspections for the SSAS are normally
the manual valves will normally be limited to general
scheduled according to the PMS, with the primary
cleaning and lubrication. Shipboard maintenance for the
emphasis on the individual components, such as the
reducing stations will include adjusting, lubricating, and
compressors, driers, dehydrators, and reducing valves.
cleaning the air inlet strainers.
Like tests and inspections for the air driers and
many of the required tests and inspections during normal
dehydrators, the maintenance of valves should be
operation. Technically, you are performing an
carried out according to the PMS.
inspection of each unit every time you take hourly
equipment readings.
BLEED AIR SYSTEMS
For the system piping, you can accomplish a
complete inspection for leaks and any other problem
As you work toward becoming a GSM2, you will
during the normal watch routine and while you are
need to be familiar with the major equipment, basic
performing valve maintenance. While you are
operations, and general maintenance of the ship's bleed
inspecting the air system, some of your major concerns
air system. You can find a detailed discussion of this
should be damaged or rusted piping, broken or missing
system in Gas Turbine Systems Technician (Electrical)
pipe hangers, and even painted or missing rubber
3/Gas Turbine Systems Technician (Mechanical) 3,
isolation mounts.
Volume 2, NAVEDTRA 10564,
Troubleshooting
In this section, we will give you only a brief
overview of the following five major bleed air systems:
In troubleshooting the SSAS, using common sense
Bleed air collection and distribution system
is your best tool. For example, visualize a situation in
which you discover a large leak in the air system.
Masker air system
Because the leak is very large, you must use the priority
Prairie air system
valve to isolate air to the nonvital header. The air
pressure, however, still does not completely restore.
Start air system
Where should you look first for the cause of this
Anti-icing air system
problem?