How Does Cabin Pressure Work in Aircraft?

Commercial aircraft fly best at high altitudes, enabling them to enhance fuel consumption and avoid adverse weather effects. While such altitudes are beneficial for flight, for humans, such heights can be detrimental. In fact, the higher we go, the less oxygen there is available to breathe because air density decreases with altitude.

At 18,000 feet, the amount of oxygen is decreased by half. Without the help of modern technology, even 8,000 feet can cause altitude sickness, also called hypoxia. Hypoxia can lead to dizziness, headaches, brain fog, unconsciousness, and eventually death. Luckily for us, aircraft cabin pressurization creates a system that controls the air entering and exiting the pressurized cabin, preventing hypoxia from occurring.

Today, commercial jets ascend to a cruising altitude of 30,000 to 40,000 feet, making this air management system critical for passenger safety. To keep the cabin pressure at a comfortable level, airplanes are pumped with pressurized air. The air that goes into an aircraft’s cabin via this process is called conditioned air. This air enters the plane’s pneumatic system through its engine compressors and is directed into the primary heat exchanger.

From the heat exchanger, the air goes through a turbine, compressor, other heat exchangers, and control valves that cool the air and regulate its pressure and temperature. Once this is done, the air is transferred into the cabin to pressurize it and control its temperature. The aircraft limits the cabin air exhaust to keep the cabin pressure at a steady level through the entire flight.

This entire process is carried out by a specific device called an outflow valve. This valve keeps the incoming air inside the cabin and releases it at a rate that is regulated by pressure controllers. As modern-day aircraft are not equipped with oxygen tanks onboard due to weight constraints, they must supplement air in the cabin from another source.

With the help of their jet turbines to suck air inside, the engines compress air, pushing oxygen molecules closer together so that it is breathable for the passengers inside the cabin. The air inside the cabin must be continuously refreshed with clean air. Therefore, fresh air from the engine must always be supplied into the cabin to pressurize it and air must always exit the cabin to exhaust away harmful contaminants, which can be done via the outflow valve.

Meanwhile, a cabin pressure regulator controls the opening and closing of the outflow valve which is in turn controlled by computers installed in the aircraft. Honeywell cabin pressure control systems, for instance, provide thrust recovery, optimize air exhaust speed for improved fuel efficiency, and more. Though cabin pressure systems are continuously being refined to offer further advantages, they still need to be routinely checked. If you find yourself in need of aircraft cabin parts or aircraft cabin pressurization components, rely on NSN Sourcing.

NSN Sourcing is a premier purchasing platform with over 2 billion ready-to-purchase items, all of which have been sourced from thousands of global manufacturers that we trust. At NSN Sourcing, we prioritize our customers’ operational deadlines and ensure that we provide unmatched cost savings on an array of select in-stock parts. As we operate with AS9120B, ISO 9001:2015, and FAA AC 00-56B accreditation, you never have to worry about the authenticity of our items. Kickoff the procurement process with a competitive quote which can be accessed via our Instant RFQ service. For additional questions, our expert team members are on standby 24/7x365. Get started today and fulfill all of your part requirements with NSN Sourcing!



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