sealing door of the chute. The chute may then be used
for manually expending miscellaneous items less than
7 inches in diameter. The size B chute has no
connecting electrical circuits.
All of the size A SLTs in both aircraft have
electrical connections that interface with the aircraft
computer. There are also connections for the manual
mode control circuits for sono inventory and
launching.
Sonobuoys, Mk 58 and/or Mk 25 marine location
markers (MLMs), and signal underwater sounds
(SUSs) can be loaded into sonobuoy launch
containers (SLCs). The Mk 25 MLMs and SUSs may
be dropped from the size B chute of the P-3C. After a
store is loaded into the SLC, with the appropriate pads
and spacers, an end cap is installed at the open end
and marked with information of the enclosed store.
The end cap has two protruding pin lugs, which mate
with slots on the SLC to Iock the store in place. The
lugs shear when the cartridge-activated device (CAD)
is fired. When the CAD fires, everything in the SLC
is ejected.
NOTE: Some sonobuoys may be received
prepackaged in disposable SLCs. This
deletes the need for loading SLCs at the
organizational maintenance level.
Before you load the SLCs into the SLTs, you
should perform a no-voltage and stray-voltage check
on the sono circuits at the sonobuoy safety switch for
the S-3A, and on the sono launch circuit tester in the
P-3C. The safety switch on both aircraft is located
adjacent to the SLTs and is actuated to the safe
position when the switch access door is open.
The SLC, with CAD installed, is loaded into a
designated SLT according to the load plan. The
locking lugs at the CAD cap mate with the locking
lugs of the SLT. The CAD is pressed against the
electrical firing pin in the SLT breech assembly. In
the S-3A, tube P2 is always loaded with an SLC
containing a search and rescue (S AR) sonobuoy.
The P-3C also has a stowage rack inside the aircraft
for 36 SLCs for use in the four SLTs inside the
cabin.
When the SLCs are loaded, the area
beneath the loaded SLTs is cleared, and the
safety switch door is closed. When the door is
closed, the cockpit sono disabled indication
will be extinguished.
A continuity check is
performed by the aircraft circuits on the CADs,
and the load status verified by using the sono
select switches of the particular aircraft. The
switch door is opened again, and the system is
disabled until just before takeoff. The load
plan is given to the tactical coordinator
(TACCO) for computer programming of the
specific store in each SLT, and in the case of
the P-3C, the stowage rack.
Release of the SLT stores in flight is normally
activated by the aircraft computer. The computer
is programmed by the TACCO and controlled by
the pilot’s or TACCO’s keyset in the P-3C. In the
S-3A, the TACCO’s keyset programs and
controls the computer. The manual release mode
is normally used only during maintenance testing
and system checks, and as an emergency backup
for the auto mode. Emergency jettison of the
SLTs is not included in the P-3C system. In the
S-3A, it is part of the jettison circuit, and when
activated, will jettison 59 of the 60 SLCs in less
than 10 seconds. Until the pilot initiates circuit
activation, the SAR buoy will remain in the P2
chute.
CAUTION
HELICOPTER SEARCH STORE SYSTEM
When either type of aircraft is on the deck,
the switch access door should be open to
prevent inadvertent firing of the SLT
stores. Inadvertent firing may cause injury
or death to personnel, and will cause
damage to the equipment.
The search store system of helicopters is less
complex than that of the fixed-wing aircraft just
discussed, but it serves the same purpose. Figure
7-22 shows some of the basic search store equipments
7-14
