Inspect the rocket catapult for damage, such as dents and corrosion; reject the unit if it has any visible defects. Inspect the head end cap for tightness by grasping the cross-shaped head end trunnion (word AFT stamped on face) with one hand and attempt to tighten the head end cap with the other. If any cap motion is detected, do not reject the unit but repair it in the following manner. Back off head end cap until the U-shaped slot in the rocket motor tube is exposed. Inspect to see if the head end trunnion pin is completely contained within the U-shaped slot. If the entire pin is not visible within the slot, reject the unit. NOTE: Pin is not necessarily bottomed in the slot.

If unit passes inspection, apply Locktite (grade N) to exposed thread area, hand tighten cap, and then tighten with strap wrench. Inspect the adjustment ring for tightness by grasping the cross-shaped head end trunnion (word AFT stamped on face) with one hand and attempt to tighten the adjustment ring with the other. If more than a few degrees of side-to-side play is evident in adjustment rings with six holes (two con-figurations of adjustment rings are in service- one with six holes and one without holes), reject the unit. If the adjustment ring without holes is found to be loose, do not reject the unit but repair it in the following manner.

Back off the adjustment ring until it contacts the head end cap, and apply Locktite sealant (grade N) to the exposed, degreased thread area. Ensure that the front body housing is tightened down against the catapult tube prior to hand tightening the adjustment ring against the front body housing. Allow Loctite sealant to set. Reinspect prior to use.

MARTIN-BAKER SJU-5/ A EJECTION SEAT

Learning Objective: Recognize the com-ponents, seat system/ subsystems, support components, system operations, compo-nent test and test equipment, and corrosion control procedures for the Martin-Baker SJU-5/ A ejection seat.

The SJU-5/ A ejection seat is a ballistic catapult and rocket system that gives the pilot a quick and safe means of escape from an aircraft. The seat system includes an initiation system that jettisons the canopy, positions the pilot for ejection, and fires the seat catapult. Canopy breakers on the top of the seat allow the seat capability to eject through the canopy should it fail to jettison. As the seat ejects from the aircraft, a rocket motor on the bottom of the seat is fired. Then a drogue gun is fired to deploy two drogue parachutes. These parachutes either remain attached to the top of the seat or they are released to deploy the main parachute, depending upon the altitude and the number of g's applied to the seat. An automatic time-release mechanism opens the main parachute container and releases the drogue parachutes that deploy the main parachute.

SYSTEM OPERATION

Before flight, the ejection seat safe/ arm handle is kept in the SAFE position. In this position, the visible portion of the handle is colored white and placarded as SAFE. When the aircraft is ready for flight, the pilot sets the safe and arm handle to the ARMED position. In this position, the visible portion of the handle is colored with yellow and black markings and placarded as ARMED. The ejection sequence (fig. 6-19) starts when the pilot pulls the ejection control handle. The up-ward movement of the handle removes two sears from the seat initiator and fires two cartridges with the seat initiator.

Firing Sequence

Ballistic gas generated by the right cartridge within the seat initiator actuates the pin puller. The gas also activates the shielded mild detonating cord (SMDC) initiator. The SMDC then activates the aircraft identification friend or foe unit (IFF) and the canopy jettison system. Additionally, it activates the inertia reel cartridge and the 0.3-second delay initiator. Ballistic gas generated by the left cartridge within the seat initiator starts the 0.3-second delay initiator. Ballistic gas pressure from either 0.3-second delay initiators ignites the primary cartridge within the catapult.