Two SMDC one-way transfers are located on the pilot and copilot bulkhead. The SMDC one-way transfer acts as a check valve or one-way detonating transfer device. The SMDC one-way transfer is a self-contained unit that houses a sealed receptacle for dual-shaped charges. Any detonation entering the inlet ports will transfer to the outlet port. Any detonation originating from the aft port (TACCO or SENSO) segment of the SMDC one-way transfer will not transfer forward. This would occur when either the TACCO or SENSO elects to cut their respective hatch. The remaining two windows and the opposite hatch would not be affected.

SYSTEM OPERATION

The S-3A aircraft canopy and hatch severence system contains two external and three internal SMDC initiator handles (fig. 2-18). Actuation of the pilot's or copilot's internal handle or either of the two external handles severs the pilot and copilot canopies, TACCO and SENSO hatches, right and left upper wing-to-fuselage fillets, and the right and left wing fillet supports.

Figure 2-18.- Emergency egress schematic.

The pilot's and copilot's internal initiator handles transfer a detonation wave signal to the connecting SMDC assemblies, which are routed throughout the cockpit area. In turn, the SMDC assemblies initiate four detonating cord assemblies, which are mounted on the periphery of the two canopies and the two hatches. The detonating cord assemblies sever or fracture the stretched acrylic canopies and hatches. FLSC assemblies, which are simultaneously initiated, sever the two wing fillet supports and the two upper wing-to-fuselage fillets, which extend into the TACCO and SENSO hatch area. Actuation of the TACCO or SENSO internal SMDC initiator will sever only the hatch, the upper wing-to-fuselage -fillet, and the wing fillet support at the crew station in which the initiator was activated. Explosive one-way transfers located forward of the TACCO and SENSO crew stations prevent the detonation wave from severing the pilot and copilot canopies.

It is virtually impossible to initiate the system at any point other than an initiator handle. As compared to hot-gas systems, this system maybe considered immune to ordinary shop hazards. The system is self-sufficient and independent. It depends upon no other system for aid or assistance, and it does not contribute aid, assistance, or sequence to any other aircraft system. The S-3A system is much less susceptible to inadvertent actuation than hot-gas systems, and hence more convenient and safe for maintenance personnel.