Anyone who flies an airplane does this but you don't know why

There is a very interesting question about airplanes but make sure you "dumb" out for a few seconds before giving an answer. So much to fly, now try to answer the super easy question below!

Question: Which side of the plane do you think of the up and down door?

Do you have the answer yet? The truth is, the plane's up and down doors are always on the left side of the plane . But why is that so?

There are quite a lot of theories set out to explain this interesting fact.

The plane's up and down doors are always on the left.

Many people say that, when designing an up and down door for airplanes, it was based on the design of the old boats, when the boat door was usually on the left.

This design supports a lot in helping ships do not clog when parked on the left of the "jetty" - opposite the pier.

Back in the past a little bit more, others say, the old warriors often move by horse and their weapons are usually swords.

Most warriors are right-handed and they will use this right hand to pull the sword out of the bag, the other hand holding the horse's reins. Therefore, for convenience, when they climb on horses, they often climb up from the left side.

However, perhaps the most persuasive hypothesis is the technical aspect of aircraft design .

Specifically, all components such as materials, food, luggage, fuel tanks are located on the right side of the aircraft.

To ensure safety, the stairs up and down the aircraft will always be on the left side of the aircraft.