CANOPY AND HATCH EXPLOSIVE CHARGE

The ends of the SMDC, while in storage or not connected in the aircraft, must be capped at all times. Any scaring or deformation of the transfer tip is cause for rejection. Any deformity here will affect the direction the blast force will travel. The tips of the SMDC act as both donor and acceptor to receive and transfer the charge from one SMDC segment to another. The tips contain Hexanitrostilbene II (HSN II) while the cord charge itself is Hexanitrostilbene I, a less sensitive material. CANOPY AND HATCH EXPLOSIVE CHARGE An explosive charge is attached to the periphery of the pilot and copilot canopies and the TACCO and SENSO hatches. The explosive charge is a detonating cord, and it is applied directly to the glass on the canopies and/or hatches. Each detonating cord assembly is held in place by a silicone rubber charge holder and fiber glass retainer (fig. 2-16). The detonating cord consists of a continuous explosive charge contained in an O-shaped seamless lead sheath. A threaded inlet port (transfer block) is mounted on the fiber glass retainer to allow attachment of the SMDC or FCDC assembly. An SMDC or FCDC connects to the transfer block at the lower front corner of each charge. Actuation of an external or internal canopy and hatch jettison initiator detonates the SMDC or FCDC screwed into the inlet port of the detonating cord assembly. The detonation wave impacts and initiates the explosive booster charge, which, in turn, initiates the detonating cord. Initiation of the detonating cord fractures the stretched-acrylic canopy or hatch along its periphery. The first half of the glass is vaporized by the heat of the flame, which slices a very narrow and deep incision halfway through it. At this point, the shock wave is sufficient to fracture the remaining thickness and spatter the glass outward. FILLET SEVERANCE EXPLOSIVE SHAPED CHARGE During emergency ground egress, FLSC assemblies sever the S-3A aircraft’s left and right upper wing-to-fuselage fillet supports. The FLSC cuts the attached fillet from the aircraft to allow complete egress through the respective hatch. The FLSC assembly is enclosed in a silicone rubber charge holder, which is held in place by a fiber glass retainer (fig. 2-17). The FLSC is a continuous explosive charge contained in a V-shaped seamless lead sheath. The silicone rubber shaped charge holder is extremely vulnerable to external damage because of the softness of the material and 0.02-inch material thickness in the area of the FLSC. A cut or tear of the charge holder, which allows the lead sheathed shaped charge to become exposed, destroys the environmental seal and requires replacement of the FLSC assembly. Figure 2-17.—Fillet FLSC assembly. 2-21