Martin-Baker SJU-5/A Ejection Seat

Description

Provides support for the aircrew during normal flight conditions and a means of escape during emergency conditions

Fully automatic system capable of:

1. zero altitude/zero airspeed ejection

2. ejection from zero altitude to aircraft ceiling

3. ejection with aircraft airspeeds up to 600 knots

Main Beam Assembly

• Forms the main structure of the Ejection Seat

• Composed of 2 vertical rectangular side beams and 3 crossbeams

Main Beam Assembly: Upper Crossbeam

Used to accept top of catapult, provides mounting for the Top Latch Mechanism and Scissor Mechanism

Main Beam Assembly: Center Crossbeam

Provides mounting for the Inertial Reel, upper attachment point for the Seat Height Actuator and for the sliding runner tubes for Seat Bucket attachment

Main Beam Assembly: Lower Crossbeam

Securing point for Seat Bucket Runner tubes

Parachute Container

• Mounted on the top forward face of the Main Beam Assembly

Parachute Container: Three Chutes

• 22-inch controller drogue

• 5-foot stabilization and retardation main drogue

• 17-foot personnel parachute

Parachute Container: Rigid Canopy Breakers

• Located on the forward corners of Parachute Containers

• Used to break the canopy during the ejection sequence in the event of canopy jettison system malfunction

Parachute Container: Headrest

• Located on the forward exterior surface of the Parachute Container

• provides support of the aircrew’s head during high acceleration and wind blast

Parachute Container: Drogue Shackle

Secures parachute withdrawal line and extender strap to Scissor Mechanism

Parachute Container: Parachute Risers

• Routed down forward side of the Parachute Container

• Connects the Aircrew’s torso harness to the parachute

Scissor Mechanism

• Attached to upper crossbeam of Main Beam Assembly

• Movable jaw is held in the closed position by the Time Release Mechanism (TRM) Plunger, opens when the TRM Plunger is withdrawn from the shackle release plunger

• Retains drogue parachutes after being deployed

• Prevents deployment of personnel parachute until TRM releases at the proper altitude and G force

Inertia Reel

• Mounted horizontally on center crossbeam

• Provides ballistic pressure for powered retraction/positioning of the aircrew during ejection and restraint to the aircrew’s upper torso during normal operation

Inertia Reel Straps

• 2 straps are wound on spools on a common shaft

• Routed through the parachute riser roller fittings and secured into the Inertia Reel locks

Inertia Reel Locks

• When straps are rapidly extended ( ex: an arrested landing)

• During high negative G loads

• Manually, by the aircrew

Back Plate

Attached by 2 spring pins to the Inertial Reel and prevents entry of FOD

Time Release Mechanism (TRM)

• Mounted on the outboard, upper right side of the Main Beam Assembly

• Automatically provides:

  • Release of the drogue via the shackle plunger/Scissor Mechanism

  • Personnel parachute deployment

  • Upper and lower restraint restraint release

TRM: Cartridge

Provides ballistic gas pressure for TRM operation

TRM: Shackle Plunger

Controls release of the Scissor Mechanism

TRM: Parachute Mechanical Lock Piston

Provides a means to retain the personnel parachute in the container until release of the stabilizer drogue

TRM: Time Delay Mechanism

Delays TRM actuation until 1.50 seconds after initiation

TRM: Barostat G Controller

Delays personal parachute deployment above altitudes of 7000 to 8500 ft until deceleration force is less than 3 G’s

TRM: Spring-loaded Firing Mechanism

Attached to the aircraft bulkhead by a trip rod and fires the cartridge

Drogue Gun

• Mounted on the outboard, upper left side of the main beam

• Ballistically deploys the controller drogue chute during the ejection sequence

Drogue Gun: Spring-loaded Firing Mechanism

Attached to the aircraft bulkhead by a trip rod and fires the primary cartridge

Drogue Gun: Primary Cartridge

Mechanically fired and ballistically deploys the drogue piston

Drogue Gun: Secondary Cartridge

Fired by ballistic gas pressure from either the TRM or Manual Override (MOR) in the event of primary cartridge failure

Drogue Gun: Piston

Attached to the controller drogue parachute via the drogue withdrawal line, deploys the controller drogue during ejection

Drogue Gun: Barrel

Retains the primary cartridge and piston, piston is retained in the barrel by a shear pin

Drogue Gun: Body

Houses the secondary cartridge

Drogue Gun: Time Delay Mechanism

Delays drogue piston deployment until 0.50-seconds after Drogue Gun initiation

Rocket Motor Initiator (RMI)

• Mounted on the center outboard, left side of the Main Beam Assembly, below the Drogue Gun

  • Forward housing contains a breech, cartridge and firing mechanism

  • Aft housing contains a coiled line (approximately 72 inches), quadrant lever, and spring plunger

  • The static line is attached to the quadrant lever on the upper end and to the Drogue Gun trip rod at the lower end

• Provides ballistic gas pressure to initiate the under seat rocket motor

Seat Height Actuator

• Mounted between the main beams

  • Upper lug is attached to the center cross member

  • Lower lug is attached to the Seat Bucket Runner

• Provides approximately 5 inches of vertical Seat Bucket adjustment for aircrew visibility and comfort

0.30-Second Delay Initiator (Two)

• Located on the aft, left side of the Seat Bucket and lower right side of the Main Beam Assembly

• Provides a 0.30-second delay between canopy jettison and seat ejection to ensure canopy is clear

Seat Bucket

• Contains all ejection seat controls

• Provides for survival kit installation

• Side structure provides aircrew protection and support

• Attached to forward lower side of Main Beam Assembly

Seat Bucket: SAFE/ARMED Handle

• Located on the right, forward corner of Seat Bucket

• Safeties the Ejection Control Handle mechanical linkage preventing accidental activation of the Ejection Seat Initiator

Seat Bucket: Ejection Control Handle

• Located on the forward Seat Bucket structure

• Connected by linkage to the 2 sears on the Ejection Seat Initiator

• Provides the aircrew with the means to initiate the ejection sequence

Seat Bucket: Ejection Seat Initiator

• Mounted under the forward center Seat Bucket structure

• Mechanically operated

• Contains 2 cartridges (right side is larger)

• 2 rigid gas lines under Seat Bucket connect the Seat Initiator to the trombone fitting on the left and right side of the Seat Bucket

Seat Bucket: Ejection Seat Initiator Right Cartridge

Provides ballistic pressure to main beam mounted 0.30-Second Delay Initiator, Inertia Reel cartridge, pin puller and Manifold Check

Seat Bucket: Ejection Seat Initiator Left Cartridge

Provides ballistic pressure to main beam mounted 0.30-Second Delay Initiator and Manifold Check Valve

Seat Bucket: Shoulder Harness Control Handle

• Located on the left side of Seat Bucket

• Locked position allows retraction and no extension

• Unlocked position allows fore and aft movement of upper torso of the aircrew

• Connected to the Inertia Reel by a linkage

Seat Bucket: Seat Height Adjustment Switch

• 3 position electrical switch, spring-loaded to the center position

• Allows aircrew to adjust the Seat Bucket height for visibility and comfort

Note: Note: Do not operate Seat Height Actuator for more than __ minute in an __-minute period

1, 8

Seat Bucket: Leg Restraint System

• Located on the forward Seat Bucket, outboard of Seat Initiator

• Two leg restraint lines, with shear rings (designed to shear at 900 lbs)

• 2 leg restraint line locks

• 2 snubbing units

• 2 upper and lower leg garters

• Provides restraint of aircrew’s legs during ejection

Seat Buckle: Under Seat Rocket Motor

• Locate on the bottom of the Seat Bucket

• Provides additional thrust allowing zero/zero ejection

• The thrust of the rocket motor is approximately 4500 lbs for 0.25 seconds

Manual Override (MOR) System

Used to release lower restraints during ground emergency egress or resumes ejection sequence in the event of TRM failure

Manual Override (MOR) System: The MOR Handle

• Mounted aft of SAFE/ARMED Handle

• Actuates the MOR Initiator or release leg restraints and seat survival kit for maintenance or ground egress

Manual Override (MOR) System: MOR Initiator

• Located inside of the Seat Bucket on the aft right side

• Consist of a cartridge and firing mechanism that is mechanically linked to the MOR Handle

Manual Override (MOR) System: Pin Puller

• Mounted on the lower aft, right side of the Seat Bucket

• The extended pin of the Pin Puller interfaces a slot in the MOR linkage to prevent MOR initiation during ground emergency egress

Manifold Check Valve

• Mounted to top of the Catapult

  • Two connecting gas lines from the right and left hand 0.30-Second Delay Initiator

  • 2 inlet ports

  • A spring-loaded locking plunger

  • Retaining pin

  • 2 check valves that ensure maximum gas pressure is maintained at the Catapult Primary Firing Mechanism

• Provides interface from Ejection Seat to the Catapult Primary Cartridge

Aircraft Seat Oxygen Survival Kit

Contains the Emergency Oxygen System and survival gear

Sticker Clips (2)

• Located on the left and right inside of the Seat Bucket

  • Accepts strap lugs from the Aircraft Seat Oxygen Survival Kit, ensures proper seat/man separation

Top Latch Mechanism

• Retains seat and catapult together

• Located on the upper left hand main beam and consists of a housing and spring-loaded plunger

  • Inboard end of the plunger is shaped to engage catapult inner piston (barrel)

  • Outboard end of the plunger is threaded to accept the top latch handwheel to allow removal and installation of catapult

  • A locking indicator gives indication of seat to catapult locked/unlocked condition

Catapult

• The initial thrust component for ejection

• Located in the center of the Main Beam Assembly and attached to the aft of cockpit bulkhead by two attachment fittings, consist of 3 barrels

Catapult: Inner Piston

• Threaded at upper end to accept the primary cartridge

• Grooved on the top outside diameter into which the top latch mechanism engages when installed

• Necked down piston head, fitted with a set of expander and piston rings located on the lower end that provides a seal between the inner and intermediate barrels

Catapult: Intermediate Piston

• Located between the inner and outer barrel

• Lengthens the extension of the catapult and adds restraint to the bending loads incurred during ejection

• Lower end of piston head is fitted with a set of expander and piston rings(Provides a gas seal between the intermediate and outer barrels)

• 12 pressure rings are installed on the intermediate barrel to absorb inertia forces during barrel separation

• Upper end contains a guide bushing riveted internally that steadies the inner barrel during ejection; the rivets are sheared when the inner barrel is fully extended (separate from inner barrels)

Catapult: Cylinder Barrel

• Accepts intermediate and inner barrel assembly

• 2 breeches are located on aft side of outer barrel to accept the auxiliary cartridges

• 2 guide rails bolted to the outside of the outer barrel mate with the main beam slippers

• Upper and lower support fittings serve as attachment points to the aircraft

• Barrel latch window is on the upper left side and allows engagement of the Top Latch Mechanism

Only ____ are authorized to perform maintenance on Ejection Seats

qualified personnel

All personnel involved in ordnance handling evolutions must be certified in accordance with _____

OPNAVIST 8023.2

To prevent firing of cartridges, ejection seat aircraft ground safety maintenance pin set must be installed and _____ must be in the ____ position

SAFE/ARMED Handle, SAFE

_____ caution must be used when handling cartridges to prevent inadvertent firing of cartridges

Extreme

The member designated as ____ shall utilize the checklist as a controlling guide. All work shall stop whenever the ____ is not in a position to observe the total scope of the work being done

Safety Observer (SO)

The second member will do the

actual procedure

The third member will be used as a

tool/cartridge handler

The checklist procedural steps shall be ___

verbal

All ___, ___, and ___shall be read aloud and acknowledged by each team member

Warnings, Cautions, Notes

Except in an emergency, the _____ process, once started, shall not be interrupted

Arm/dearm

During the removal/installation procedures, the cockpit, upper fuselage, and wing areas will be “____” to all other personnel

OUT OF BOUNDS

Removal/Installation procedures contained in the ____

A1-F18AC-120-600 Checklist, Challenge and Reply

The steps are identified with ___ designation at the end of the step

(QA)