Things are different when you fly and we have come to accept it as normal. If you went to eat a meal at a restaurant you wouldn’t expect a waiter to wait on your every need yet we except the flight attendant to do everything. The meals themselves would likely be refused if they turned up in a restaurant but they are an exciting part of any flight. And of course, there are the windows. The windows in an airplane are stranger than any window you have ever seen yet you likely never questioned it. Picture the windows of your home, picture the windows of your work or school, picture the windows of your car. What do they all have in common? They are all square or rectangular in design. Airplane windows are not, they are circular. But why?
The reason is not one of aesthetics. As you can imagine every decision that is made in the design of an airplane is done to either make money or keep you safe. When these two ideas conflict we hope the airline will choose the safest option but we know they don’t always do that. For years planes flew with square windows and it was a complete success, there were no issues at all.
One day someone very intelligent realized that if planes flew higher in the air, there would be less drag and it would cost less to make journeys. Planes then needed to fly at 30,000 feet as this was decided to be the most economic point of flying. A decision made to make money, not for our safety. Slight changes were made to the plane to ensure they could fly at this higher altitude. Sadly many of these changes came through experience.
One change was that the fuselage, where the passengers are, needed to be a cylinder to help distribute air pressure. A second change required was that the windows needed to be circular. At least three accidents have been documented from the 1950s where planes that flew higher resulted in crashes. They killed a total of 56 people and in each of the three cases the windows were found to be the cause. It turns out the if you have square windows you have corners. Corners are a point of weakness in the window and the pressure builds too high. This results in three known plane wrecks and possibly many more.
Airlines then realized that if they changed the windows to circular the problem would be solved. They also increased the layers of glass in the window to ensure the air pressure couldn’t be changed by the outside environment. You may have noticed that airplane windows have a small hole in them. Don’t worry this is not letting air in from the outside. This is actually allowing normal air distribution between the second and third pane of glass to ensure there is no imbalance.
One other thing you may have noticed on an airplane is that the window sometimes does not line up with the seat. This can be incredibly annoying when you want to look out the window for a view or you are resting your head on a piece of the window and the person behind you opens it because they feel it is their window too. There is a reason for this as well. This is because when a plane is manufactured it is done with a certain amount of seats in mind but it is up to the airline that purchases the plane whether they stick with the recommend amount or try to fit more on. Again, in the interest of money, most airlines try to fit on more seats.
These are the three key bits of interest when it comes to airplane windows. The next time you are on an airplane have a look around and see what other strange things are in place that we seem to take as normal.