The downloading breech mounts to the bulkhead. The
downloading breech cap screws onto the downloading
breech. With the downloading breech cap removed, the
downloading breech lets you insert the loading,
unloading, cleaning, push rod tool so the stores can be
easily removed during downloading procedures. It also
prevents air pressure buildup in the tubes when
uploading stores. Reinstall the downloading breech
caps after the loading or unloading procedures have
The manifold has eight manifold breech lead
receptacles for connection of the breech leads. It also
has two test socket assemblies you can use during
dispenser electrical test procedures.
The stepper switch provides sequential firing of the
impulse cartridges. The switch has 10 functional
settingsone safe setting, one arm setting, and eight
firing steps. Always place the stepper switch in the safe
position during dispenser loading and unloading. Move
the switch to the arm position during aircraft arming
procedures just before flight.
Forward and Aft Retaining Lock
Each of the four dispenser tubes contains a forward
retaining lock, an aft retaining lock, and an arming
The forward and aft retaining locks, when in the
locked position, protrude into the dispenser tube. This
prevents loaded stores from being inadvertently ejected
by the forces during aircraft catapult launches.
The forward retaining lock is located between the
dispenser outer skin and the tube near the midpoint of
the dispenser. You can move the retainer lock from the
either the locked or unlocked position through an
access door located on either side of the dispenser.
Before loading a store, rotate the retaining lock to the
unlocked position. This pivots the retainer lock out of
the tube. After the store has been loaded, rotate the
retaining lock to the locked position, and secure it by
installing a shear pin. The forward retaining lock
retains the forward-loaded store only.
The aft retaining lock is attached to the aft bulkhead
and retains the aft loaded store. It is also secured in the
locked position by installing a shear pin.
The arming mechanism is located in the aft end of
the dispenser tube. The arming mechanism initiates the
arming sequence of a store as it is ejected from the tube.
The dispenser is suspended by two screw-type lugs
spaced 14 inches apart. The area around the suspension
lugs has a hardback reinforcement to permit sway
bracing and forced ejection of the dispenser.
Two electrical receptacles, V1 and V2, are located
forward and aft of the suspension lugs, respectively.
Both receptacles give you a way to electrically connect
the dispenser to the aircraft weapons control system.
Only one receptacle is used at a time. The electrical
configuration of the rack determines the receptacle you
An electrical wiring harness is routed internally
from electrical connectors V1 and V2 to the stepper
switch. A safety switch that is normally in the closed
position interrupts the wiring harness. When the safety
pin and flag assembly is inserted, the safety switch is
held in the open position and the electrical circuits are
grounded, making the dispenser electrically safe.
When you load a dispenser tube with munitions,
each pair of flares are configured with an ADU-381/A
flare adapter kit.
A yellow-colored sealing ring is pressed on each
end of the munition as a seal between the munition and
the tube body. This prevents gas pressure from escaping
during ejection. A green-colored arming cap is installed
on the timer end of a flare or on the rotochute end of a
sonobuoy. The green arming cap lanyard is connected
to the timer knob of the flare, and then pressed on over
the flange of the sealing ring. Mount a white
cross-shaped plastic spacer on the aft sealing ring of the
forward munition. This provides enough space between
the forward and aft munition to provide an expansion
chamber for ejecting the aft munition.
After you have installed the adapter, install the
munitions in the dispenser tube.
When an SUU-25F/A dispenser is fully loaded and
uploaded on the aircraft, the pilot may eject flares. The
pilot must first select the weapons control system, and
then trigger the dispensing switch. A 28-volt dc
electrical signal passes through an electrical cable from
the aircraft to either receptacle J1 or J2 of the dispenser.
The signal is routed from the dispenser receptacle to the