Window/Hatch Severance System
The emergency egress system provides a means
of escape from the aircraft for crew members after
ditching or after a wheels-up landing by initiation
of explosive charges to blow out windows and
hatches. The S-3 emergency egress system is
distinguished from hot gas and actuator systems
by its use of shielded mild-detonating cord
(SMDC) instead of hot gas and explosive charges
instead of actuators. The S-3 system is much less
susceptible to inadvertent actuation than hot gas
systems, and more convenient and safer for
maintenance personnel.
The S-3 emergency egress system (fig. 6-7)
consists of two window-hatch external jettison
handle/initiators, three window/hatch internal
jettison handle/initiators, window and hatch-
severance explosive charges, fillet-severance and
fillet-support severance explosive-shaped charges,
SMDC’s, and SMDC manifolds or one-way
transfers.
FUNCTIONAL DESCRIPTION.— The S-3
emergency egress system is initiated from any one
of five positions—two on the outside of the flight
station, and three located in the crew compart-
ment at the eyebrow panel and at the TACCO
and SENSO instrument panels. All windows
and hatches are cut and blown outward by
the actuation of either exterior window/hatch
external jettison handle/initiator, and by the
pilot’s,/copilot’s interior window/hatch internal
jettison handle/initiator. The TACCO and
SENSO window/hatch internal jettison handle/
initiators cut only the respective panel next to the
crew member, The system is used primarily for
ground and water rescues. The handle/initiators
have a trigger action. Once the system is actuated,
the system will respond to completion without
further action by crew members. The functional
sequence is from the handle/initiator (any one)
to the SMDC, to the explosive charge, which is
the actual cutting tool for the window or hatch
glass. If either or both the TACCO and SENSO
hatches are to be blown, the respective fillet and
fillet support will be cut to allow complete egress
of the hatch. When either the TACCO or SENSO
crew member actuates the handle/iniator, the
opposite hatch and the two flight station windows
will not be cut, since an SMDC manifold (check
tee) or one-way transfer restricts transfer of
pyrotechnic energy flow to one direction.
The emergency egress system is entirely self-
sufficient and completely independent. The system
does not depend on any other aircraft system, nor
does the system aid, assist, or sequence with
another system. The SMDC system is more
reliable and much faster than a comparable hot
gas system. The system is safer from the stand-
point of inadvertent actuation due to the
extremely high initiating velocities and pressures.
The high operating velocity is much too fast to
permit system initiation by ordinary sawing,
filing, drilling, or hammering. With quick-release
safety pins properly installed, the system is
virtually inert.
COMPONENTS.— The following items are
components of the window/hatch severance
system.
Window/Hatch External Jettison Handle/
Initiator.— Two external jettison initiators are
installed inside access doors on each exterior side
of the aircraft just below and forward of the wind-
shield aft posts, The external cartridge-activated
initiator (fig. 6-8) is a mechanically fired device,
Figure 6-8.—External cartridge-actuated initiator.
6-13
