If you have traveled at least once with the plane, you may have noticed that there is a small hole at the bottom of each window. What is her role?
It is not the fault of a manufacturing defect, nor the age of the aircraft, because that must be all the windows in the plane. You do not have to worry if you notice these holes, but only if you do not notice them.
They have a very important role in keeping the cabin pressure at a normal level during the flight. In the event of a depression, only the outside window will break, not the interior window, so that the lives of the passengers will not be endangered, writes Daily Mail.
Each window in the plane consists of three layers: the outer, the middle and the inner window. The inner layer is made of a combination of glass and acrylic to be as durable as possible.
The small hole that you can see is made in the middle window to maintain a balance of pressure between the inner and the outer glass.
If the outside window is destroyed during an incident, the interior will be strong enough to maintain normal pressure and the pilot will have enough time to lower the plane at a lower altitude or even land.
Also, airplane windows have an oval shape to provide better visibility to passengers. In addition, the corners of a square or rectangular glass would concentrate the pressure in these areas and in time the windows would crack.