How Do Airplanes Get the Oxygen We Breathe?

As a plane flies, fast-moving air enters both the jet turbine engines. This fast-moving air is compressed as it passes through layers of fan blades inside the turbine. It’s at the compressor stage that a portion of the hot air is ‘bled off’ from within the turbine. Therefore, the air generated at this point is known as bleed air. Now, this bleed air is very hot, with a temperature range of a couple hundred degrees Fahrenheit, so it needs to be cooled first. That’s why this hot bleed air is allowed to expand and pass through a heat exchanger so that it cools to a comfortable temperature. This cool, filtered air is then dispersed in the passenger cabin at a pressure that humans can comfortably breathe.