Ejector seat

A ejector seat is a security system aiming at allowing the pilot and the crew of a Avion to escape from this one when it becomes unverifiable or is about to be crushed.

This system is mainly used in the military aircrafts.

Operation

The trip of the ejection is done using a handle located between the legs or at the top of the head of the pilot.

The first stage is the opening of the canopy which is:

is ejected using explosive bolts to detach it and to jacks which half-open it, the relative wind is then enough to make it leave
is simply weakened using an explosive cord drowned in glass which does it étoiler like a windshield of car

The pilot is then plated on his seat, his legs brought back behind and his immobilized arms. The supply Oxygène rocks then on a bottle fixed at the seat.

The explosion of powder cartridges made spread a telescopic tube at which the seat is fixed, and pushes it out of the cockpit. A Rocket motor starts then to give to the seat sufficient altitude and speed to quickly move away it from the plane.

A stabilizing Parachute is spread and the seat starts to go down again. As soon as various conditions as altitude are correct, the pilot is released from his seat and a Parachute of descent opens to make it land.

Time between the request for ejection and the opening of the stabilizing parachute is lower than three seconds. A parcelling of survival fixed at the seat is released at the same time as the pilot is released from his seat.

On certain planes, the ejector seats are replaced by ejector capsules or cockpits: in this case, it is the complete cockpit which is separated from the fuselage then slowed down by parachutes, the crew remaining with the shelter inside until the arrival on the ground. This technique makes it possible to evacuate the plane at high speed, without the crew not undergoing the shock due to the air volume displacement. This system is in particular employed on the F-111 Aardvark and XB-70 Valkyrie.

Sit zéro-zéro

The first models of seats were usable only under certain conditions of altitude and speed. Since, the ejections are possible even starting from a motionless plane on the ground (for example on a carpark, in the event of serious fire with the starting of the engines). Such seats are called zéro-zéro (for altitude zero/speed zero).

Test on the ground of the ejector seat of a McDonnell Douglas F/A-18 Hornet:

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