Pressurize is a verb which comes from the English expression to pressurize. This is the action that is developed to protect, in a certain area, the normal conditions of atmospheric pressure , even if abroad this pressure is very different.
In order for an aircraft to fly, it is imperative that its cabin be pressurized since, otherwise, the oxygen available inside the plane would be insufficient and its occupants would face various disorders, such as headaches or dizziness. In the most extreme cases, pressurization problems can cause death .
To pressurize the cabin, the planes have a environmental control system . In this way, a part of the air entering the aircraft's engine is diverted to a compressor. This machine warms said air and sends it to the passenger cabin, making the amount of oxygen per unit volume similar to that found in low altitude areas, even when the plane is flying at high altitude.
It is important to keep in mind that airplanes only withstand a certain pressure difference between inside and outside. When this difference is larger than they can bear, a explosion .
Therefore, so that an airplane can fly without the crew and passengers suffering problems, it is not enough to pressurize the air. It must also be checked that there is a certain Balance between the internal pressure and the external pressure, something that is done automatically (with a system that allows some air to escape when the internal pressure rises too high) but which can also be controlled manually.
The use of the technique Pressurization in aircraft dates from the 1930s, since the Boeing B-307 Stratoliner already had a pressurized cabin. In addition, it made it possible for the flight engineer to be part of the crew to control this subsystem, as well as fuel pressure, power levels and the route, allowing the pilot to devote all his attention to the control of the aircraft.
Despite having achieved this achievement before the Second World War , since barely a dozen of Boeing B-307 Stratoliner , most of the aircraft used during this unfortunate page in the history of mankind reached great heights without any pressurization; to compensate for the lack of this characteristic , the pilots had to wear oxygen masks.
Not pressurizing the cabins of the warplanes entailed different complications, in addition to the obvious danger to the pilot . In larger bombers, for example, more than two people had to travel, so there was a separate area for passengers, and it was not convenient to provide everyone with oxygen masks, since this need hindered the proper organization and implementation of March of the strategies.
The bomber B-29 Superfortress arrived to solve this problem: it appeared in 1944, after almost two years of test flights, and it was the first to have a pressurized cabin , although only for passengers . It was used mainly by North America in the final stage of World War II and also in the Korean War, in which they faced their southern and northern extremes with the support of powers such as China and the Soviet Union, in addition to the Hollywood land mentioned.
It is worth mentioning that the developer of the system in charge of controlling the cabin pressure of the B-29 Superfortress, Garrett AiResearch Manufacturing Company , took advantage of the knowledge bequeathed by Boeing for its already veteran Stratoliner.