Gate 41

Things that look scary but have an explanation

Why might oxygen masks drop?

What would actually happen if the masks fell?

If cabin pressure is lost, the masks drop automatically (at a cabin altitude of about 14,000 feet). At cruise altitude you could have only seconds to tens of seconds of useful consciousness, so you put your own mask on first, then help others.

Pull the mask toward you to start the flow. The bag may not inflate: oxygen is still flowing. Most aircraft use chemical oxygen generators that supply roughly 12 to 20 minutes of oxygen, which is enough time for the pilots to descend to an altitude where the air is breathable.

The pilots have their own masks and a separate oxygen supply. The cabin crew will guide you. A warm mask and a slight burning smell are normal for the generator.

A little deeper

Generators burn a sodium chlorate core to release oxygen, which is why they get hot and cannot be turned off once started. This keeps them simple and reliable, with no pressure bottles in the ceiling.

Emergency descent profiles aim for about 10,000 feet. At that altitude people can breathe without supplemental oxygen.

Honest limits: decompression events are very rare. The system is there precisely so that they are survivable.

See it in Gate 41, in the cabin

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