To arm the seat, you rotate the handle down and
aft. When in the ARMED position, the portion
of the handle that is visible to the pilot is colored
yellow and black, with the word ARMED
showing. In the SAFE position, the visible portion
of the handle is colored white, with the word
SAFE showing. By placing the handle to the
SAFE position, it causes a pin to be inserted into
the ejection firing mechanism. This prevents
withdrawal of the sears from the dual-seat
initiators.
LEG RESTRAINT SNUBBERS. As the seat
travels up the guide rails during ejection, the leg
restraint lines, which are fixed to a floor bracket,
are drawn through the snubbers. Inertia draws the
legs against the front of the seat bucket, and the
legs are retained in this position by the leg restraint
lines. When the lines become taut and a pre-
determined load is attained, the special break rings
fail and release the lines, leaving only a short loose
end protruding from the snubbers. The leg lines
are restrained by the snubbers, and the legs
secured until the taper plugs are released from
their locks when harness release occurs.
EMERGENCY RESTRAINT RELEASE
HANDLE. Rotation of the emergency restraint
release handle to permit emergency ground egress
will rotate the cross shaft of the lower harness
release mechanism to release the lower harness
locks, leg restraint line locks, and negative-g strap
lock. Full rotation of the handle to withdraw the
sear of the firing unit is prevented by the pin puller
engaging the rear end of the slot in the emergency
restraint release operating link.
SHOULDER HARNESS CONTROL LEVER.
The shoulder harness control lever, mounted on
the left side of the seat bucket, is connected to
the inertia reel, and provides manual control for
the shoulder straps. In the forward position, the
shoulder straps will be locked, and in the aft
position, the shoulder straps will be unlocked so
the occupant will be free to turn and move about.
SEAT HEIGHT ACTUATOR SWITCH.
The seat height actuator switch controls electrical
power to raise and lower the seat bucket to suit
the needs of the occupant.
PIN PULLER. During ejection, gas from
the RH seat initiator cartridge enters the pin puller
plunger housing and lifts the plunger out of
engagement with the groove in the piston.
Movement of the plunger allows gas to enter the
cylinder and withdraw the piston out of
engagement with the slot in the emergency
restraint release operating link, the piston being
held in the operated position by residual gas
pressure. The operating link is then disengaged
from the lower harness release cross shaft by the
action of a spring-loaded plunger in the operating
link guide bracket mounted on the seat bucket
side.
LOWER HARNESS RELEASE MECHA-
NISM. When the sequencer fires the barostatic
release unit cartridge, the piston in the RH ballistic
manifold acts on the harness reel cross-shaft lever.
It rotates the cross shaft to withdraw the plungers
in the upper harness locks and release the shoulder
harness reel straps. At the same time, gas passes
via the RH ballistic manifold down the RH
trombone tube assembly, entering the emergency
restraint release piston housing and face-firing the
cartridge. The combined gas pressure from the
two cartridges operates the emergency restraint
release piston, operating the linkages to release
the lower harness locks, the leg restraint line locks,
and the negative-g strap lock.
Parachute Canopy and Drogue
During the ejection sequence, the parachute
deployment rocket motor fires, extends the
withdrawal line, and withdraws the parachute in
its bag. The parachute canopy emerges from the
bag, periphery first, followed progressively by the
remainder of the canopy and the drogue. The
extractor rocket and bag clear the area. The
drogue and crown bridle impart a force on the
canopy, proportional to airspeed, to inhibit full
canopy inflation until g-forces are reduced.
Rotation of the emergency restraint release
handle to permit emergency ground egress will
rotate the cross shaft of the lower harness release
mechanism to release the lower harness locks, leg
restraint line locks, and negative-g strap lock. Full
rotation of the handle to withdraw the sear of the
firing unit is prevented by the pin puller engaging
the rear end of the slot in the emergency restraint
release operating link.
During ejection, gas from the RH seat initiator
impulse cartridge enters the pin puller plunger
housing and lifts the plunger out of engagement
with the groove in the piston. Movement of the
plunger allows gas to enter the cylinder and
withdraw the piston out of engagement with the
slot in the emergency restraint release operating
5-33
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