The fixed oxygen system in the cabin supplies oxygen to passengers and cabin crew in case of cabin depressurization (Cabin Altitude > 14000 ft)
It has containers with two to four masks and a chemical oxygen generator.
In case of cabin depressurization the container doors open automatically and the oxygen masks drop out.
The container doors can also be opened from the cockpit or manually with a special tool placed in the cabin crew workstation.
A chemical system has the following characteristics:
–There is an independent chemical generator, which is fired when the mask is pulled. Afterwards, it’s not possible to stop the oxygen flow.
–The oxygen flow and supply pressure are independent of the cabin altitude.
–The oxygen is supplied to passengers for a specific period of time, which can either be 15 or 22 minutes.
Author – Zinhom Mohmoud – Aviation Training Consultant