Importance Of Having An Oxygen System:
The human body is dependent on oxygen. As the altitude increases, the consequent decrease in pressure reduces the amount of oxygen the human body can absorb when breathing. To enable flight at high altitudes either the aircraft cabin has to be pressurised to replicate the pressure at a lower altitude, or the occupants of the aircraft have to be given supplemental oxygen.
Oxygen systems are designed to store or to generate a supply of pure oxygen and to regulate, dilute as required and then distribute that oxygen to crew or passengers. In cases of emergency, such as in the event of smoke, fire, fumes or loss of pressurisation, the provision of oxygen is available.
A320 Oxygen System
The A320 oxygen system consists of:
- Cockpit Fixed Oxygen System
- Cabin Fixed Oxygen System
- Portable Oxygen System
Cockpit Fixed Oxygen System
It consists of high pressure cylinder(s) which is capable of supplying oxygen to 4 crew members through full face quick donning masks stowed in readily available boxes adjacent to the seats of the crew in the cockpit i.e. the Captain, the First Officer and two more occupants (if needed).
A mask mounted regulator is used to control the supply of oxygen in various ways:
A mixture of air & oxygen, pure oxygen or emergency pressure control.
Cabin Fixed Oxygen System
In case of depressurisation, the masks stowed in the overhead containers of the passenger seats drop down automatically to provide supplementary oxygen to the passengers.
Chemical generators are used to generate oxygen for the cabin.
The generation of oxygen starts only when the passenger pulls the mask towards them. There is no regulator to control the supply, it is supplied at a constant pressure.
Portable Oxygen System For The Flight Crew
The flight crew smoke hood located on the right, backside of the cockpit ensures the eyes and respiratory system protection of one flight crew member when fighting a fire and in case of smoke or noxious gas emissions or cabin depressurisation.
The smoke hood is also based on a chemical air regeneration system.