When most people choose a seat, they always like to choose a window position to enjoy the scenery, but have you noticed that there is a small hole in the bottom of the porthole of the airliner?
In fact, the higher the altitude, the less oxygen there is to breathe. Without oxygen, people suffocate to death. This is felt even more intensely for people who trek through high altitudes. For example, in Lima, Chile, the oxygen saturation in the air is about 21%, and the air pressure is 760 mm Hg.
The higher the altitude, the lower the air density
When a person goes up, oxygen saturation remains relatively proportional and air density decreases, which means that the percentage of oxygen per breath also decreases. The higher the altitude, the lower the distance between the oxygen molecules. For example, at an altitude of 11,000 feet (about 3,300 meters), oxygen saturation levels are 40% lower than sea level, and atmospheric pressure is about 480 mm Hg.
Aircraft need to be pressurized when flying above 10,000 feet
If the aircraft were flying at an altitude of 10,000 meters, it would be unimaginable without an oxygen mask, and now the cabin of an airliner usually needs to be pressurized. Aircraft are now pressurized when flying above 3 kilometers so that both passengers and crew can breathe normally. They can do this by pumping jet engines into the cabin. Once the cabin reaches the ideal pressure, it is maintained by leaving a valve. If the air pressure in the aircraft cabin exceeds the designed air pressure, the outflow valve will open and drain the air. Once the correct pressure is reached, the outflow valve will close.
Aircraft cabin pressurization allows passengers to stay in a comfortable environment, but it is not so friendly for the aircraft, and it needs to have a way to release the pressure. This is the small hole in the window. The next time you take a flight, you can take a closer look at this window and you'll see that it's not just a pane, but three pieces of plexiglass.
You can touch the innermost window. This window is specifically designed to control the air pressure difference between the cabin and the outside air. Small vent holes in the windows help balance the pressure difference between the cabin and the outside air.
In addition, small holes in the bottom of the windows release moisture and prevent frost or condensation from blocking the passenger's view.
What happens if the plane suddenly loses its stress?
If the cabin suddenly loses pressure for some reason, the oxygen mask will fall off the top. Many people believe that the oxygen in this comes from gas cylinders, or compressed air that people use when scuba diving. The tank containing the oxygen is too heavy and impractical. Oxygen masks derive oxygen from chemical reactions.
The oxygen in the oxygen mask comes from the combination of sodium chlorate, barium peroxide and potassium perchlorate to produce oxygen. Once the chemistry starts, you can't stop giving you ten to twelve minutes of oxygen. That's enough for the pilot to lower the plane below 10,000 feet, and then you can breathe normally.
Why do aircraft need to cruise at an altitude of 10,000 meters?
There are two reasons, 1, the aircraft can fly faster. 2) It is more effective in terms of money. If regions on The Earth are higher than 8,000 feet, they are generally considered high altitudes.
As we all know, the highest point on earth is Mount Everest, located on the mainland, at an altitude of 8848 meters. The most populous high-altitude region on Earth is El Alto in Bolivia, where nearly 1 million people live at 13,600 feet (4,145 meters) above sea level.
Altitude is related to air pressure, and pilots measure their altitude using an altimeter. The higher the plane flies, the lower the air pressure. This behavior occurs for two reasons:
- Earth's gravity pulls air as close to the Earth's surface as possible.
- The higher the climb, the smaller the number of gas molecules in the air, which means the less chance of nitrogen, oxygen and carbon dioxide colliding with each other, what climbers call "thin air."
Lower air pressure also means less oxygen in the air to breathe, which is why aircraft are pressurized to compensate for the lack of air pressure at high altitudes.
Everyone has heard that if an airplane loses its pressurization for some reason, an oxygen mask is deployed over your head. Typically, passengers will have about 10 to 14 minutes of oxygen. This gives the pilot enough time to descend below 3,000 meters, where he can breathe normally.
The higher you fly, the more efficient you are
The reason planes cruise at high altitudes is that they burn less fuel and they can fly faster because of the lower density of air. Flying at altitudes above 10,000 meters also means the plane can avoid weather systems, making passengers more comfortable.
Engines on modern jets are called turbofan engines and are most efficient when used at high altitudes. Jet engines operate more efficiently under maximum speed or exhaust temperature limits. Due to the thin air, the engine produces less thrust when the aircraft is raised. This means that the aircraft can fly faster while burning less fuel.
Everything has to do with air density
The higher you walk, the less dense the air, which means less friction or resistance on the plane. At high altitudes, you need less thrust to propel the plane. A good explanation is with water and syrup. If you move your hand over a bathtub filled with two liquids at the same speed, you need to use more force to pass through the syrup because it is denser than water. This is the same principle as when an aircraft is flying at low or high altitudes.
Low altitude like syrup, high altitude like water.