bottle and the ECU are mounted on top of the
launcher assembly. A servicing valve is provided, on
the left-hand side of the helicopter, for servicing the
air bottle. The air bottle should be serviced to
1200-1250 psi. This ensures that the system will be
able to launch all 25 sonobuoys.
The distributor valve assembly uses a stepping
motor to route air pressure to the selected launch tube.
A manual selection knob, distribution lock, and
tube-selected indicator window are located on the
valve. The manual selection knob can be hand rotated
to move the rotary valve to vent or to any desired
launcher tube position.
The valve lock allows the
rotary valve to be manually secured to any desired
launcher tube position or vent. The tube-selected
indicator window displays the position of the rotary
valve at any one of 25 tubes or vent.
The ECU front panel contains three controls
and one indicator.
The controls are a
AUTO/MANUAL switch, a SELF TEST switch,
and a SAFE switch. The indicator is a STATUS
display. When the AUTO/MANUAL switch is in
the AUTO position, the ECU controls the rotary
valve. In the MANUAL position, the rotary valve is
controlled by manually turning the manual selection
knob. Depressing the SELF TEST switch initiates
the BITE testing for the ECU and the launcher. The
STATUS indicator displays any faults found during
self-test. If more than one fault is found, the failure
codes will cycle at 3-second intervals. The SAFE
switch causes the rotary valve to move to the vent
FIXED-WING KILL STORE SYSTEMS
The kill store system consists of all equipment
necessary to select, arm, and release weapons from
the bomb bay(s) and wing stations of the aircraft. The
system is divided into two subsystemsthe bomb bay
and the wing store systems.
Bomb Bay System
The bomb bay system consists of the units and
components necessary for the carrying, arming, and
releasing of stores.
On the P-3C, these stores are
installed on bomb racks suspended from removable
pylon assemblies, which are mounted across the
center of the bomb bay. On the S-3A, the racks are
attached to brackets mounted to the aircraft in a
cruciform pattern. Each of these basic installations is
assigned a station number. Numbers followed by
letters (such as A or B) designate these stations for
special capacities or types of stores. In addition, these
stations are arranged in pairs: stations 1 and 2,
stations 3 and 4, etc. As a further identification
feature on the P-3C, the stations are grouped into two
layers. Odd numbered stations in the upper layer and
even numbered stations in the lower layer. When the
bomb bay is loaded with mixed stores, each pair of
stations must be loaded with the same type of store to
ensure proper clearance between the stores. The S-3A
has only one layer of stations because of its much
smaller bomb bays.
The bomb bay doors are electrically controlled
and hydraulically operated. For ground maintenance
without power, the doors may be opened or closed
internally on the P-3C by a manual control valve and
hand pump. On the S-3A, the doors can be operated
externally with a 3/8-inch drive crank. Both aircraft
have a ground safety pin that is used to disable the
door mechanism in the open position. The door safety
pin must be inserted when personnel are working in
The release of bomb bay stores is normally
accomplished by the computer.
In the P-3C, the
TACCO performs programming, and the pilot or
TACCO controls the release. In the S-3A, the
TACCO does both, with the copilot acting as backup.
The pilots in both aircraft have final control because
they must activate the master arm switch.
Wing Store System
The wing store system consists of the units
and components necessary for carrying, arming,
and releasing external stores. On the P-3C, these
stores are suspended from 10 wing stations,
numbered 9 through 18. On the S-3A, the stores
are suspended from two wing stations, W5 (left)
and W6 (right).