We almost always expect to board from the left side of a plane when at the airport. This tradition is as old as the passenger aviation industry. But why do we usually enter an aircraft from this side?

Azul Getty
Boarding from the left-hand side is usually the standard procedure. Photo: Getty Images

Crew requirements

Designers planned pioneering airports so that planes could taxi in front of the terminal and disembark travelers. It was helpful for the captain to make judgments about wing clearance from the terminal building and to put the plane door in front of the terminal doors. Some early systems had right-side doors into the cabin. However, the pilot did not have the same unobstructed view.

Moreover, a Boeing 787 captain told The Daily Mail that the service doors on the right-hand side are smaller to keep more rigidity in the plane's structure. The larger the door, the more reinforcement is needed around its composition. Therefore, since passengers were passing through the left-hand side, it made sense for the captain to also sit on the left-hand side to maneuver the aircraft to a standstill.

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Turkish 787-9 Dreamliner
Passengers board most jets, such as the Boeing 787 Dreamliner, from the left. Photo: Getty Images

Safety comes first

The Civil Aviation Authority summarizes this practice as being a necessity when it comes to safety. Altogether, it makes sense to separate passengers from the professional activity that usually occurs on the other side of the plane.

"Access to the aircraft holds is usually only on the right side of the aircraft, meaning there will be movement of vehicles on this side, and refuelling on many (but not all) large commercial airliners is conducted on the right side of the aircraft," the CAA said, according to The Daily Mail.

"A clear separation of passengers from ground servicing activities mitigates the risk of passenger injury from moving vehicles."

Passenger movement is also better to be away from other activities such as unloading baggage and cargo. At times, these jobs require plenty of space and workers. So, having passenger activity on the left-hand side allows more room for movement.

Ethiopian Airlines cargo
The airline has been supporting its cargo department by utilizing otherwise dormant passenger aircraft amid the pandemic. Photo: Getty Images

An age-old tradition

The process of boarding on the left can be traced back to naval practices. Ships have a port, which is on the left side and a starboard, which is on the right side. Passengers would embark and disembark on the port side. Subsequently, since planes are an evolution of passenger travel, there was a natural continuation of these practices.

Nonetheless, there are exceptions to the rule. For instance, fliers board several smaller planes, such as the Mooney M-20, from the right-hand side. This process allows the pilot to enter before the passenger sitting adjacent. Additionally, in times of emergencies or inconvenience, there may be situations where it would make sense to use a larger aircraft's right door for customers.

Altogether, regardless of the origin of this practice, it makes logistical sense to board on the left-hand side. If opposite patterns start to emerge, it could be costly to adjust to the new systems.

What are your thoughts about passengers usually boarding from the left? Have you ever boarded from the right? Let us know what you think of the process in the comment section.