Why is There a Hole in Airplane Windows?

An airplane is basically a sealed container traveling at high speeds and at great heights, through the air. So, if it is supposed to be sealed then why is there a hole in airplane windows?? Is it not a safety hazard? Let’s find out.

If you’ve ever got hold of one of the coveted window seats on the plane, you may have noticed a small hole in the window. Don’t panic, this is not a misconstruction. It is a very small hole but that might scare you if you think that you are sitting in an oxygenated metal container that is supposed to have no airflow from outside. But why is there a hole in airplane windows?

The pressure outside the airplane, at great heights is very low and the airplane maintains the pressure inside to almost 1 atmosphere, as you feel when you live on the earth and not flying. The holes are designed to equalize the pressure. The aircraft windows in most passenger aircraft consist of three panes. The outer and middle pane can withstand the pressure difference between the outside world and the aircraft cabin.

However, the inner window pane, the one that you can touch as a passenger, is not pressure-tight. It usually consists only of plexiglass and serves as protection for the passenger. Because the two outer panes can get very cold in the air, so cold that one could get frostbite.

Besides, the exterior windows can fog up due to the temperature difference between the cabin and the outside air. The hole prevents this by keeping the pressure stable between window panes and thus maintaining the temperature.

Suggested Read: Will We Travel Through Space in the Future?

Reduce Pressure to a Minimum

Another peculiarity of aircraft windows is their shape. The windows as well as the emergency exits and doors are always round. There is also a physical reason for this. If they were angular like most windows and doors, the plane could crack. The round shape, on the other hand, is ideal for distributing the corresponding loads of the aircraft. The pressure on the material is reduced to a minimum.