At lower altitudes, our lungs effortlessly take in the necessary oxygen. However, ascend to 10,000 ft above sea level and you’ll notice it becomes harder to breathe due to the thinning oxygen. This is where the concept of an “aircraft cabin being pressurized” comes into play. It ensures you can breathe as if you’re at sea level, even when you’re soaring above 10,000ft. Wondering how aircraft pressurization functions?
Think of an aircraft as a gigantic life support system in the sky, akin to a spaceship. Just as the atmosphere becomes scanty with oxygen above 10,000ft, being inside an airplane is akin to being encompassed by a massive oxygen mask. This pressurization system maintains normal oxygen levels for you, even when cruising at 40,000 ft.
Why Cabin Pressurization is Essential
Airplanes typically cruise at altitudes between 30,000 and 40,000 feet. A Concorde can cruise at an altitude of 50,000 feet. At these heights, the air pressure is much lower than what we are accustomed to at ground level. If an aircraft’s cabin were not pressurized, passengers might suffer from serious health issues, including sickness, loss of consciousness, and even death.
At ground level, air pressure is suitable for the human body, supplying the appropriate amount of oxygen. But as we ascend, the air pressure decreases, leading to a lack of oxygen. For example, at 16,000 feet to 20,000 feet, the air pressure is almost half that of the pressure at the ground. This drop in pressure would require most people to use oxygen masks above 18,000 feet to breathe.
The symptoms of reduced oxygen at high altitudes can range from nausea and breathlessness to more severe issues like dim vision or slower thinking. Therefore, the pressurization of the airplane cabin is essential to maintain an air pressure level comfortable for passengers and to mitigate the effects of rapid altitude changes during takeoff and landing.
How Cabins are Pressurized
The process of pressurizing the cabin is carried out using vents in the aircraft’s engine. Modern commercial airlines contain vented rotors located behind the engine’s fans. These outflow valves, controlled automatically or manually by pilots, are responsible for maintaining the desired cabin pressure.
When the cabin pressure needs to be lowered, the outflow valves open to allow air flow. This process, also known as bleeding the air inside the cabin, is controlled through the opening and closing of the valve. The valve continues to function throughout the flight, ensuring a fresh cycle of air every 2 to 3 minutes.
In some aircraft, engine combustion is used to supply pressurized air. This hot combustion air not only pressurizes the cabin but also protects the engine and wings from ice buildup at high altitude.
What if a Plane Loses Cabin Pressure?
A sudden loss of cabin pressure is a serious situation, and it prompts oxygen masks to drop from overhead compartments to provide an emergency oxygen supply to passengers. Even with the availability of oxygen, a depressurized cabin can pose risks such as hypothermia and hypoxia.
Pilots are trained to respond to cabin depressurization by gradually descending to an altitude of around 8,000 to 10,000 feet, where passengers can avoid health injuries related to a loss of pressure.
Despite the dangers of depressurization, flying at a lower altitude to avoid these risks is not an option. Low-altitude flying exposes the airplane to other dangers like mountainous terrain, lightning, and adverse weather conditions. It also makes the flight less fuel-efficient, time-consuming, and costly.
Flying Safely in Comfort
I hope that this explanation has provided you with a clearer understanding of why oxygen masks will drop from the overhead compartments if there’s a loss of cabin pressure. It emphasizes the importance of paying attention to the safety demonstration or safety video before taking off. Failing to wear your masks correctly in such situations could lead to impaired judgment, loss of consciousness, and even death.
This article should also help you grasp why the cabin must be pressurized and how it enables you to breathe at extremely high altitudes. You’ll come to realize that nearly everything within an aircraft serves a specific purpose, with the majority of these functions centered around ensuring our safety during the flight.
First love never dies. I fell in love with airplanes and aviation when I was a kid. My dream was to become a pilot, but destiny led me to another path: to be an aviation digital media content creator and a small business owner. My passion for aviation inspires me to bring you quality content through my website and social accounts. Aviation is indeed in my blood and blog!
