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How Escape Slides Inflate?

No one wants to get off the plane through this slides but if you have seen one deploying we can agree it´s impressive how fast such a big slide can inflate.

31 July 2019, 07:01

No one wants to get off the plane through this slides but if you have seen one deploying we can agree it´s impressive how fast such a big slide can inflate.

Evacuation time required by the FAA is 90 seconds using 50% of the evacuation exits which leaves slide deployment a maximum of 10 seconds (now slides do it within 6 seconds), having a volume of about 25 cubic meters how they manage to inflate?

The system used for inflation is a non-explosive inert gas inflation system. Using a lightweight aluminium cylinder and aspirators the required time is reached with no problems. The cylinder is equipped with a regulating valve and in its interior has carbon dioxide and nitrogen at more than 3,000 psi which makes just a third of the slide´s capacity, the remaining is filled with the aspirator making use of the pressure in the cylinder to suck external air.

Aspirators used in evacuation slides (surrounded red)

Other aircrafts such as A380 use a gas generator module and instead of an aluminium cylinder with compressed air it haves a coolant chamber made of carbon composite in which interior haves liquid carbon dioxide and high pressure nitrogen and carbon dioxide gases. When the inflation system is activated the gas generator squib burns the propellant to create hot gases that later will be introduced in the coolant chamber when the burst disk rupture occurs because of the pressure, and gases are cooled to an acceptable level and send to the slide through a regulating valve which then uses aspirators as in the first inflation system explained.

Inflation system with gas generator module found in A380

This inflation systems are activated when a door opens being armed if it doesn´t inflates a red handle will be available to pull and initiate inflation. In older aircarfts the door was armed placing physically the crew members the girt bar attached to brackets either in or adjacent to the door sill now this is done placing the door in armed mode.

Girt bar in planes such as B737 are physically placed

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