CHAPTER 17
Ejection
17.1 EJECTION
The ejection seat must be used to escape from the aircraft inflight. If the canopy fails to jettison
during the ejection sequence, the seat will eject through the canopy.
17.1.1 Ejection Seat Restrictions. During ejection seat development and testing, the SJU-17(V) 1/A
and 2/A NACES seats were qualified for use by aviators with nude weights from 136 to 213 lb. The
minimum and maximum nude body weights allowed by OPNAVINST 3710.7 Series for those on
aviation duty are 100 lb and 235 lb, respectively. Therefore, a gap exists between the ejection seat
certified weight range and the weights of the current aviator population.
Due to NACES ejection seat limitations, any person whose nude body
weight is less than 136 lb or greater than 213 lb is subject to increased risk
of injury from ejection.
The ejection seat catapult was designed for the qualified weight range only. Ejection seat stability
is directly related to occupant restraint. All occupants should be properly restrained in the seat by the
torso harness for optimum performance and minimum injury risk. Inertial reel performance may be
degraded for occupants outside of the certified weight range
17.1.1.1 Injury Risks - Nude Weight Less than 136 lb. Lighter weight occupants are subject to a
higher risk of injury due to the following factors:
1. Excessive pull back during inertial reel retraction.
2. Poor positioning during ejection.
3. Greater acceleration during catapult firing.
4. Higher parachute opening shock during ejections near the upper end of Mode 1 (approaching 300
KCAS).
5. Seat instability during drogue deployment during ejections above 300 KCAS.
17.1.1.2 Injury Risks - Nude Weight Greater than 213 lb. Heavier weight occupants are subject to
a higher risk of injury due to the following factors:
1. Poor positioning during ejection due to insufficient pull back during inertial reel retraction.
2. Insufficient altitude to clear the aircraft tail structure.
3. Insufficient altitude for full parachute inflation in zero/zero cases or at extremely low altitude/
airspeed.
A1-F18EA-NFM-000
V-17-1 ORIGINAL
4. Higher descent rates during parachute landing.
17.1.1.3 Airspeed during Ejection. Ejection analysis shows:
1. Optimum speed for ejection is 250 KCAS and below.
2. Between 250 and 600 KCAS, appreciable forces are exerted on the body, making ejection more
hazardous.
3. Above 600 KCAS, excessive forces are exerted on the body making ejection extremely hazardous.
When possible, slow the aircraft before ejection to reduce the forces on the body.
Never actuate the manual override handle inflight, as ejection would then be impossible and the
aircrew would be unrestrained during landing. When the manual override handle is actuated, the
ejection seat SAFE/ARMED handle is rotated to the SAFE position, the aircrew is released from the
seat, and the harness cannot be reconnected.
If the seat becomes unlocked and slides partially up the rails, ejection
and/or parachute deployment is still possible but the ejection handle
must be pulled, followed by activation of the manual override handle.
Under these circumstances, low altitude ejection capabilities are compromised.
17.1.2 Low Altitude Ejection. The minimum altitude required for a successful ejection is dependent
on sink rate, airspeed and bank angle, and airspeed and dive angle. The effects of sink rate are shown
in figure 17-1. The effects of airspeed and bank angle are shown in figure 17-2. The effects of airspeed
and dive angle are shown in figure 17-3.
The decision to eject at low altitude must be based on these factors to ensure a successful ejection.
Additionally, ejection seat trajectory is improved if the aircraft is zoomed to a higher altitude prior to
ejection initiation. The additional altitude increases time available for seat separation and parachute
deployment. However, do not delay the decision to eject if the aircraft is nose down and cannot be
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