In the middle of the last century the aircraft of the commercial airlines they began to fly at higher altitudes, a move they intended to reduce costs, since lower air density meant less drag on the plane. plane and therefore less fuel.
so that the aircraft In order to fly at a higher altitude, the engineers also had to modify the design, the cabin had to be pressurized and the device acquired a cylindrical shape.
It was thought that these two innovations would be enough and that air safety was fully guaranteed, however, this was not the case.
The problem was in the windows.
On April 7, 1954 the elegant Havylland Comet G-ALYP -with four turbojet engines- took off from Rome airport bound for London. Shortly after passing through Naples, while flying over the island of Stromboli, the plane suffered a terrible accident and disintegrated. After a few months, another plane with similar characteristics crashed in the same place, this time it had left London and its destination was Johannesburg.
As a result of these two unfortunate events, an exhaustive investigation was carried out to determine the causes of the accident. In both cases, the investigators discovered the existence of numerous cracks in the remains of the fuselage, at the level of the corners of the windows.
At that time, the airplane windows were square in shape, which caused a enormous tension in the corners, which favored that when the pressure was too high the window would break and explode. The engineers calculated that 70% of the cabin pressure was concentrated precisely at those points.
round windows appear
In a very short time the design was modified and the windows of the planes became round, in this way the pressure was distributed throughout the structure and the flights became much safer. In other words, the design of the current windows is the result of an innovation related to security and not for aesthetic reasons.
Las aircraft windows They are made of plastic and glass. The innermost layers are made of plastic, while the outermost, the most resistant, is made of glass. Its size varies according to the model of the plane, with the most modern having a surface similar to that of an A4 page.
And also a hole
At the bottom of the plane windows is a small and apparently insignificant hole. This hole is not connected to the outside atmosphere, but to the internal structure of the plane and to the last layers of the fuselage, so that pressure and humidity can be maintained.
The perforation of the windows allows the pressure of the passenger cabin to equalize with the rest of the layers that the window has in a homogeneous way. If not for her, the pressure difference could cause the inner layers of the window to crack and could break. But that’s not all, it has an additional function, preventing the window from fogging up due to temperature differences and moisture escaping, preventing the interior layers from freezing.
One last curiosity, the windows located in the nose of the plane are different from those of the rest of the plane, since they have to withstand possible impacts and a much higher pressure.