Can Airplanes Reverse on Their Own on The Ground?
Airplanes are genuine wonders of our modern time, helping us connect the globe as such vehicles can traverse several thousands of miles in just hours. While being so advanced, some may wonder why aircraft are without certain features that a typical automobile would have, such as being completely devoid of a reverse gear. Most of the time, one will see a ground vehicle tug attached to the aircraft which is responsible for the aircraft's ground movement in certain areas and during specific operations. Although aircraft are more than capable of moving on the ground on their own during operation, pilots often avoid taking advantage of such capabilities for certain reasons., In this blog, we will discuss how an airplane can reverse without having a reverse gear and why they utilize the help of a ground vehicle for ground movement. Let us begin by looking at how airplanes can reverse on their own.
How Do Airplanes Reverse on Their Own?
Though airplanes do not have a reverse gear like other vehicles such as cars, the aircraft has one unique feature known as powerback. However, this system is not a preferred option for reversing and is only used if the pilot is left with no other options. Powerback is the process of using the jet engine to create forward thrust for the means of moving in the reverse direction.
Standard fuel combustion in a plane's engine creates hot gas which is blown out through the back of the assembly. Newton's third law, which states “to every action, there is an equal and opposite reaction,” causes forward thrust, helping move aircraft forward at cruising speed. Reverse thrust, on the other hand, follows the same process of combustion, but instead expelling it in the opposite direction. Instead of the air being pushed backward at high speeds, its direction changes, and the air flows forward, creating a force that pushes the aircraft in the reverse direction.
Pilots also choose not to use reverse thrust when taxiing or parking the aircraft. Normally, the reverse thrust of a plane is used to slow it down before landing after reaching a certain altitude limit. The backward force slows down the plane, making it easy to handle and land on a runway. Once the aircraft touches the runway, slowing the aircraft is entirely dependent on the use of brakes and not reverse thrust. However, pilots cannot use this mechanism while in standard flight because the engine would create too much drag on itself and damage its internal components.
Planes of smaller sizes can reverse their airflow completely, whereas larger planes can only partially achieve this. In order to make it easier for larger aircraft like the Boeing 767 and 777 to traverse a runway, ground vehicles known as pushback tractors are used. These tow bars can be seen alongside an airplane's nose wheel, where they will use their hooked end to carefully guide the aircraft's movement while being pulled by another vehicle toward a waiting point. Smaller planes, however, do use reverse thrust to move backward.
Why Do Aircraft Not Reverse on Their Own?
Planes choose to use ground vehicles instead of reverse thrusters because using a tug from a ground vehicle is much cheaper. Another reason is the fuel required for reverse thrusting is a lot more than a pushback tractor will need to push or pull the aircraft. Since the plane will only move back when turned on, burning fuel is inefficient. Consuming more fuel is expensive and harms the environment by releasing more carbon dioxide than a pushback tractor. Apart from air pollution, reverse thrust also creates noise pollution, discomforting passengers and the airport staff. Reverse thrust can also harm the engine when operated on the ground as there can be a lot more dirt and debris present, which can enter the engine, causing damage or wear and tear. Due to these various risks, pilots rarely use reverse thrust because there are too many downsides to the mechanism that make it only useful in the case of emergencies.
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