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.

Figure 6-9.- Internal canopy/ hatch severance initiator.

Figure6-10.- Pilot/ NFO window-severance linear shaped charge.

with the firing pin relaxed (not precocked) before handle actuation. The sear mechanism is a conventional ball-and-node type, which disengages completely after 3/ 4-inch of travel. During travel, the firing pin withdraws, but the handle does not disengage. The primer fires into a lead azide charge, which fires the output charge. The external jettison initiators have no safety pins, but use a 10-foot lanyard to protect against inadvertent initiation. Either external initiator will cause all windows, hatches, fillets, and fillet supports to blow away from the aircraft.