With the safe and arm handle in the down or ARMED position, an upward pull on the ejection control handle removes the two sears from the firing mechanisms and causes the two cartridges within the initiator to fire. Gas pressure from either cartridge will initiate seat ejection.

Manual Override Initiator

Aft rotation of the manual override handle positions the safe and arm handle up to the SAFE position and releases the lower restraint. In this position, the pin puller engages a slot in the manual override handle linkage and prevents actuation of the manual override initiator. During the ejection sequence, the pin puller is retracted inboard. This allows the manual over-ride initiator to be actuated and override the automatic sequencing. Gas pressure from the manual override initiator is piped to the time-release mechanism and the secondary cartridge in the drogue gun.

Pin Puller 

During the ejection sequence, gas pressure from the right seat initiator cartridge enters the pin puller and operates a spring-loaded ball lock. This allows the -pressure to retract the pin and disengage it from the manual override linkage.

Seat Survival Kit The seat survival kit is opened by operating the release handle located on the right forward side of the kit. During the ejection sequence, the oxygen hose and communication lead disconnect from the aircraft. The emergency oxygen and radio beacon are automatically actuated. During parachute descent, the pilot may operate the release handle to open the survival kit. This allows deployment and inflation of the life raft. The life raft and survival equipment are connected by a lanyard to the survival kit lid, which is attached to the pilot.

Manual Override System

Operation of the manual override handle will rotate the cross shaft of the lower harness locks, leg restraint line locks, and the negative-g strap lock. This is necessary for emergency ground egress from the aircraft. Full aft rotation of the handle is prevented by engagement of the pin puller piston in a slot of the manual override handle linkage. This prevents firing of the manual override initiator.

During the ejection sequence, gas pressure from the right seat initiator cartridge operates the pin puller to withdraw the pin puller piston from the slot in the manual override handle linkage. In the event of a time-release mechanism failure or drogue gun failure above barostatic altitude, aft rotation of the manual override handle will fire the manual override initiator. Gas pressure from the manual override initiator cartridge operates the lower harness release system. It will also pass up the trombone fitting and fire the time-release mechanism cartridge. This cartridge operates the upper harness release mechanism, scissor mechanism release plunger, and parachute lock. Additionally, the gas pressure passes to the drogue gun and fires the secondary cartridge.

Leg Restraint System

As the seat travels up the guide rails during the ejection sequence, the leg restraint lines are drawn through the snubbing units. This action pulls the pilot's legs aft against the seat bucket. As the seat continues to rise, the leg restraint lines become taut. When the force on the bottom fittings reaches approximately 900 pounds, the shear ring will shear. The shearing releases the lower portion of the leg restraint lines.

Automatic Harness Release System

Firing of the time-release mechanism cartridge moves the piston and connecting rod down and rotates the cross shaft. Rotation of the cross shaft releases the inertia reel locking plungers and releases the inertia reel straps. Simultaneously, gas pressure is routed down the trombone fitting to fire the cartridge in the manual override initiator. Gas pressure from the manual override initiator cartridge presses against the head of the piston. Movement of the piston rotates the bell crank lever and releases the spring-loaded locking plungers of the lower harness locks. This releases the lap belt lugs and rotates the cross shaft. Rotation of the cross shaft releases the looking plungers in the leg restraint line and negative-g strap locks.