MIL-DTL-9479E (USAF)
3.2.16 Precautions against improper component installation. Cartridge-actuated devices,
propellant-actuated devices, and other replaceable components shall be designed to preclude
improper installation which could adversely affect the proper functioning of the seat system or its
subsystems (see 4.5.2).
3.2.17 Stabilization subsystem. Provisions shall be incorporated for seat-man stability during free
flight, including the period from rocket ignition through recovery parachute deployment. The
stabilization subsystem shall become effective at the time of seat-aircraft separation and shall
include the following characteristics (see 4.5.8):
a. Counteract rotations caused by the eccentricity between the dynamic cg and the rocket
thrust line, and by aerodynamic forces.
b. Control the application of deceleration forces. The ejection seat shall be stabilized in such
a manner that the neutral direction of aerodynamic deceleration is eyeballs out or eyeballs in.
Damped oscillations about the neutral direction of aerodynamic deceleration shall not exceed
20° in the pitch or yaw plane.
c. Maintain optimum attitude for recovery parachute deployment.
d. Stabilize the seat-man combination during free fall to the pressure altitude setting for
recovery parachute opening, following a high altitude ejection.
3.2.17.1 CG envelope. The cg envelope applicable to the stabilization subsystem for the seat
system shall be the broadest envelope determined by surveying crew member body sizes and
authorized equipment combinations. Based upon the static cg locations for the full range of crew
members, the cg envelope shall include a +2.0 inch tolerance about each individual cg with respect
to the rocket thrust line. The relationship of rocket thrust line to cg envelope shall be in
accordance with the principle shown on figure 2; however, the cg envelope must not necessarily
be totally above the thrust line (see 4.5.8).
3.2.18 Parachute recovery subsystem. The parachute recovery subsystem shall incorporate an
Air Force approved and qualified canopy and shall be fully automatic upon ejection control
actuation. The initiation of the recovery parachute shall be controlled by a multimode velocity,
acceleration, or force-sensing device and an aneroid. The pressure altitude of the recovery
subsystem shall be 15,000 + 1,000 feet. At altitudes below this setting, the recovery parachute
shall be deployed in the minimum time after ejection, consistent with human tolerances. The
parachute shall be released from the crew member by the actuation of not more than two releases
(see 4.5.8).
3.2.18.1 Manual parachute deployment. Provision shall be incorporated for manual parachute
deployment following ejection. An actuation handle for manual deployment shall be provided
which can be easily reached and actuated by the crew member. The control shall be actuated by a
force not greater than 27 pounds, using only one hand (see 4.5.1, 4.5.8).
3.2.18.2 Seat-man separation. Seat-man separation shall be accomplished by the deployment and
inflation of the recovery parachute. This separation shall be positive and shall prevent seat
interference with the man or parachute (see 4.5.1, 4.5.8).
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