Aviation is amongst the greatest achievements in the modern human history. It connects the world and pushes globalization by allowing people to travel around the world and delivering cargo in short periods of time. Airplanes themselves are marvels of engineering, showing how far humanity has come and how much it has achieved. There are countless facts about aviation and airplanes themselves, most of which are related to the science and engineering of planes and the way they operate. However, the vast amount of people are not really interested in that; they are more keen on finding out some commonly rising questions that do not require a scientific explanation with specific terms.

Here are 7 facts about aviation industry that you have probably been wondering about.

How do we get breathable air on an airplane?

Have you ever asked yourself where is the breathable air coming from when on an airplane?

A modern commercial airplane cruises from approximately 10 to 12 kilometers, which is considered the “sweet spot” for flying (more on that later). At that altitude, the supply of air is not a problem; there is actually enough of it. However, the issue is that it is not a breathable air as the pressure of the oxygen in it is too low to be directly inhaled by humans.

So, how do we actually get fresh, breathable air when flying? Of course, the long answer would involve an in-depth explanations, terms and formulas, but there is a simplified answer. As the plane flies, fast-moving air enters the jet turbine engines located on the wings of the plane. The air is compressed as it passes through the blades of the engine, however, at this stage, the temperature of the air could reach almost 100 degrees Celsius. Therefore, it has to go through a heat exchanger, which cools it down to a comfortable temperature for inhalation. Finally, the cool enough and filtered air is dispersed into the passenger cabin.

Additionally, an outflow valve, which is usually located at the back of the cabin, makes sure that the used air is vented out, and so the air in the cabin is always fresh.

How high do airplanes fly and why?

As mentioned earlier, the optimal altitude for commercial airplanes to cruise at is between 10 and 12 kilometers and there are several reasons for that.

One of the main ones is fuel efficiency. At that altitude the air in the atmosphere is very thin, which means there is less resistance for the airplane to pass through it. As a result, the airplane needs less effort to maintain the speed, thus uses less fuel. But what would happen if airplanes would fly at a higher altitude to get less resistance? At that point, it would create problems for the engines as they need oxygen to work, which is very sparse at higher altitudes and is not sufficient for the engines to operate properly.

Avoiding traffic and hazards is another reason. It is usually the traffic of light aircraft, helicopters, drones and even birds. All of that can be avoided by flying higher.

Moreover, flying that high provides pilots with the time in case of emergencies, where they would need a solution for a certain situation or a preparation for an emergency landing.

Airplane tires are not filled with air

This might be a bit surprising and unusual, but airplane tires are inflated by nitrogen rather than oxygen to prevent them from catching fire and exploding during landings.

The tires on an airplane face an incredible amount of pressure during landings due to braking and high speed. As a result, they reach incredibly high temperatures, so the oxygen inside the tires would react with the heat resulting in an explosive fire outburst. Nitrogen, on the other hand, is an inert gas and does not react with the rubber inside the tire, making it much safer.