Figure 5-1.-Forward ejection seat; (A) right-hand view, (B) left-hand view—Continued.
zero speed, zero altitude in a substantially level
attitude to a maximum speed of 600 knots
estimated air speed (KEAS) between zero altitude
and 50,000 feet.
Ejection is initiated by pulling a seat firing
handle situated on the front of the seat bucket
between the occupant’s thighs. The parachute
container is fitted with canopy breakers to enable
the seat to eject through the canopy should the
jettison system fail. After ejection, drogue
deployment, man/seat separation, and parachute
deployment are automatically controlled by an
onboard multimode electronic sequencer. A
barostatic harness release unit caters for partial
or total failure of the electronic sequencer, and
an emergency restraint release (manual override)
system provides a further backup in
failure of the barostatic release.
the event of
The seat is ejected by action of the gas pressure
developed within a telescopic catapult when the
cartridges are ignited. An underseat rocket motor
situated under the seat bucket is fired as the
catapult reaches the end of its stroke, and sustains
the thrust of the catapult to carry the seat to a
height sufficient to enable the parachute to deploy
even though ejection is initiated at zero speed, zero
altitude in a substantially level attitude. The seat
is stabilized and the forward speed retarded by
a drogue and bridle system, followed by automatic
deployment of the personnel parachute and
separation of the occupant from the seat. Timing
of all events after rocket motor initiation is
5-3
