Q. Is it true that once oxygen masks drop down, they only provide about 15 minutes of oxygen?

A. It all depends on the altitude the plane is flying at. You’ll use more oxygen at a higher altitude like 40,000 feet vs 30,000. Typically, as soon as the masks come down, the pilot descends to as low an altitude as possible and finds the nearest airport to land.

They never keep at the higher altitude they were flying at. At 12,000 or 15,000 feet you can breath fairly normally— it’s like being at the top of a mountain. So the pilot does a rapid descent to a breathable altitude which should only take 10-20 minutes depending on the altitude they were flying when the depressurization happened. In any case, as they descend the oxygen lasts longer and longer until it’s no longer needed.

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