How Does Cabin Pressurization Work on Aircraft?

At the high altitudes in which aircraft fly, the air surrounding the plane is much cooler and thinner than at ground level, making it unsafe to breathe. Nevertheless, while some oxygen tanks are stored on board for passengers that require it, the vast majority of air in the cabin is sourced from outside the plane. However, to avoid the issue associated with breathing the thin air at high altitudes, the outside air is warmed and pressurized before entering the cabin. To maximize efficiency, this entire process is facilitated by the jet turbines, which naturally release hot, pressurized air as a byproduct. To learn more about cabin pressurization, read on as we discuss the ways in which this process supports modern aviation.

Why Cabin Pressurization is Important

As stated before, cabin pressurization is highly important to the safety of all on board an aircraft. Our bodies are designed to function on ground level where the concentration of oxygen in the air is generally between 15% and 20%, such as in the areas where most people live. Conversely, at 30,000 feet, the cruising altitude for most commercial aircraft, the percentage of oxygen is a mere 6.3%. When exposed to air such as this, which not only has far less oxygen, but also a much lower atmospheric pressure, our bodies experience hypoxia. Characterized by a below-normal level of oxygen in your blood, hypoxia can cause confusion, shortness of breath, irregular heart rate, and more that can ultimately lead to irreparable harm. With that said, too much pressure is also a concern. According to the U.S. Federal Aviation Administration (FAA), airplane cabins must be pressurized to no more than that of 8,000 feet. If the cabin is pressurized beyond this point, other types of injuries may occur.

The Mechanics of Cabin Pressurization

Airplanes are able to achieve the appropriate amount of cabin pressurization by pumping fresh air into the cabin while simultaneously releasing stale air. As such, aircraft typically have a valve near the tail, known as the outflow valve, which is only opened when the cabin pressure increases beyond the limit at which the structure is rated. At the opposite end of the system, fresh air is brought in via the jet turbines. As these large turbines spin, they heat and compress atmospheric air to be mixed with atomized fuel and ignited. However, some of this hot, condensed air is siphoned away into the body of the plane to both heat the wings and fuselage, as well as to provide pressurized air to the cabin. As the plane flies, it is constantly taking in and releasing precise amounts of fresh and stale air to maintain the proper cabin pressure. Not only does this setup regulate cabin pressure, but it also ensures the cabin air is fresh as stale air can cause problems by itself. If the air inside of the cabin is never changed, passengers will be more likely to spread transmittable illnesses, such as viral and bacterial infections.


When considering the effects of breathing the thin air found at cruising altitudes, it is clear that without the cabin pressurization advancements we have achieved, aviation never would have made it to the level we have reached today. As such, it will always be important for plane owners and operators to maintain these systems to the best of their ability. Whether you require cabin pressurization system parts or other aircraft components, ASAP NSN Hub has you covered. Explore our inventory of aviation-grade items at your leisure or request a quote for your comparisons today on any item(s) of interest using any Request for Quote (RFQ) form on our site. Partnered with a wide network of supply locations, you can always count on us for convenient fulfillment solutions that can match your budget, operational requirements, and time constraints with ease.


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