gas-operated components of the post-ejection sequencing subsystem (fig. 6-41). CATAPULT LOCK AND UNLOCK MECH- ANISM.— The catapult lock consists of a lock- ing piston and six locking balls set between the inner and outer catapult tubes. The catapult lock retains the seat in the cockpit during inverted flight. Upon seat ejection, the lock is released by gas pressure from the catapult cartridge. Catapult cartridge gases move the locking piston upward and permit the locking balls to disengage from the groove in the outer catapult tube. This action removes all connection between the inner and outer catapult tubes. DROGUE CHUTE AND CONTAINER PROJECTION.— When the outer catapult tubes have moved upward approximately 16 inches on the inner tubes, gas pressure is applied to the pistons attached to the drogue container. There is one piston in each outer tube. When the pistons exit the top of the outer catapult tubes, the drogue container and parachute move up and aft of the seat. Then, aerodynamic pressure is applied to the container. This causes stretching of the drogue bridle and loosening of the drogue container flaps. The drogue suspension lines and canopy then emerge while the container and associated hard- ware are jettisoned (fig. 6-42). TROMBONE ASSEMBLIES.— Two pairs of trombone assemblies are associated with the catapult. The outer trombone assemblies route ballistic gas from two M99 ejection initiators to the catapult cartridge igniters. The inner trombone assemblies route ballistic gas pressure from the catapult tube assemblies to components of the post-ejection sequencing sub- systems and to both seat-back rockets (SBR). They also route ballistic gas pressure from the 7,000- and 14,000-foot aneroid-actuated initiators to the parachute container opener (fig. 6-40). Sustainer Thrust Subsystem During either mode 1 or mode 2 operation, two SBR motors provide the thrust necessary to propel the seat and pilot to an altitude sufficient to attain terrain and aircraft tail clearance and to allow personnel parachute deployment and infla- tion. Each SBR has dual-ignition inlet ports. Ballistic gas pressure from both catapult tube assemblies is ported into both SBRs to provide redundant ignition. This pressure fires internal SBR igniters, which ignite the propellant grain for a burn time of approximately 0.25 second (fig. 6-40). DART Stabilization Subsystem The directional automatic realignment of trajectory (DART) stabilization subsystem, com- posed of a bridle, a brake assembly, and two nylon slip lines, provides stabilization for the seat and pilot during low-speed ejections. Stabilization is accomplished by correcting any misalignment of the seat and pilot center of gravity relative to the SBR thrust center line. One end of the bridle is permanently attached to the under side of the seat bucket. It acts as a hinge during DART operation. Cables attached to the other end of the bridle restrict the arc of the bridle to a predetermined angle. This ensures optimum operation. Part of each slip line is stowed in a protective fabric housing routed through the brake assembly. The remainder of the two slip lines is stowed in a second protective fabric housing after being routed through fairleads on the bridle aft side. Free ends of the slip lines are attached to the catapult cartridge manifolds of the ejection seat. Slack in the slip line permits the seat to travel through seat tip-off and initial rotation, which results from center of gravity and thrust center line misalignment. Tension developed in the slip lines by the brake assembly imparts a correcting moment to the seat and pilot. This is necessary to counteract excessive seat and pilot pitch rotation and also to provide trajectory control. Post-ejection Sequencing Subsystem The post-ejection sequencing subsystem includes all gas-operated and cartridge-actuated devices required to initiate operational mode sequencing functions. It also includes the WORD rocket motor, the primary means for personnel parachute deployment in the inertia-WORD (I- WORD) rocket motor deployment sequence of mode 1, and the backup means for the drogue- WORD deployment sequence of modes 2, 3, and 4  . Personnel Parachute Subsystem The personnel parachute subsystem includes a WORD bridle assembly, riser assemblies with lanyards, spring-loaded internal pilot parachute assembly, main canopy assembly, ballistic spreading-gun assembly, and an override and 6-58