You might wonder about the reason for using the left side only of the plane to board and deplane passengers from the aircraft. There are many points of view about this case, some say that it is because of safety sides, and following old designs or other means of transport. So let’s understand the case.
Some experts explain that one of the reasons is the traditional nautical custom. US air force pilot explained that airports were designed so the aircraft could stop in front of the terminal to discharge passengers, this helps the pilot to control the wing’s position in front of the terminal building and keep the plane’s door in the convenient position with the terminal’s door. Some old means of transport have doors on the right side of the passengers’ cabin, but the pilot’s view comes first.
Another point of view comes from Andrew Stagg, a commercial pilot who says that the cause returns to ships that have a port side (left) and starboard (right) side. The passengers were embarked and disembarked through the port side, so the designers of airplanes and jetways follow the same design.
For other safety reasons, passengers’ movement should be on one side to avoid confusion for the passengers, and because the other side is usually used for the fueling process, loading, unloading baggage and cargo away from embarking, and disembarking passengers.
Most modern planes deplane and board from the left-hand side and run technical orders from the right-hand side. Until the 1960s, before the construction of jet bridges, airplanes would often park close to and parallel to the terminal.
While the captain sits on the left and the pilot is responsible for taxiing and parking, it is easier and the pilot can judge and control better. Nowadays, airplanes have followed this historic habit. Airplanes are fuelled on the right, bags are loaded on the right and most of the cleaning & catering vehicles also park on the right-hand side. which reason do you feel is more convenient?
Source: aviationforaviators.com