Can you fly at 12000 feet without oxygen?
No, you cannot fly at 12000 feet without oxygen. The atmosphere at this altitude is too thin to provide enough oxygen for humans to breathe. At 12000 feet, the atmospheric pressure is only about half of what it is at sea level, and the oxygen concentration is only about one-third of what it is at sea level. This means that the amount of oxygen available to breathe is much less than what is required for humans to survive.
The human body needs oxygen to produce energy and to function properly. Without enough oxygen, the body cannot produce enough energy to sustain itself, and the person will start to feel lightheaded and dizzy. As the altitude increases, the amount of oxygen available decreases, and the person will eventually pass out if they do not get enough oxygen.
At 12000 feet, the air is so thin that it is not possible to get enough oxygen to sustain life. Even if you are wearing an oxygen mask, the amount of oxygen available is still not enough to keep you alive. The only way to survive at this altitude is to use supplemental oxygen, either from a tank or from a pressurized cabin.
At 12000 feet, the air is also very cold. Without protection, the cold air can cause frostbite, hypothermia, and other cold-related illnesses. The thin air also makes it difficult to breathe, and the lack of oxygen can cause altitude sickness. Altitude sickness is a condition that can cause headaches, nausea, and dizziness. It can even be fatal if it is not treated quickly.
In conclusion, it is not possible to fly at 12000 feet without oxygen. The atmosphere at this altitude is too thin to provide enough oxygen for humans to breathe, and the cold air can cause serious health problems. The only way to survive at this altitude is to use supplemental oxygen, either from a tank or from a pressurized cabin.