mechanisms and provides a mounting for the
survival kit assembly, rocket motor, and backpad
assembly. The seat bucket assembly is configured
for a particular seat by adding application-
peculiar components, such as a seat height
actuator. The bucket is secured by four nuts to
studs incorporated into sliding runners on the
seat’s main beams. Interference devices on the rear
of the seat bucket and on the main beams
assembly ensure that only the correct seat bucket
is installed in forward and aft cockpits.
The back of the seat bucket contains a rigid,
molded pad that forms the back rest. It is
contoured so that when the seat occupant is
automatically pulled back by the shoulder harness
reel when ejection is initiated, he/she assumes the
correct posture. A cushion attached to the
backrest provides additional comfort for the seat
occupant.
Contained within the lower rear corners of the
seat bucket are the lower harness locks and release
mechanism. These are connected by a cross shaft
and connecting links to the leg restraint line locks
located in the side plates. The same connecting
links connect the negative-g strap lock that is
situated in the floor of the seat bucket to the rear
of the seat firing handle. Half way up the inner
face of the seat bucket sides are sticker clips. The
pin puller is mounted at the rear of the seat bucket
on the lower right-hand side (fig. 5-2).
UNDERSEAT ROCKET MOTOR.— The
underseat rocket motor (fig. 5-20) is a sealed unit
and consists of a manifold (machined, drilled, and
threaded to accept ten propellant tubes), a lateral
thrust motor tube, a cartridge tube, and four
efflux nozzles. The propellant tubes are
Figure 5-21.-Operating controls.
Figure 5-20.-Underseat rocket motor Mk 123 Mod 0 (forward seat).
5-18
