You’ve probably taken off and landed in an airplane a few times in your life. Airplanes are truly wonders of modern times, helping us connect the globe. Distances that took weeks, months, or even years to cover can now be covered in less than a day’s time.
So, can airplanes reverse on their own? Yes, airplanes can reverse on their own. After an airplane lands on the runway, it needs to taxi outside the runway before the passengers can get off. And like with a car, this requires reversing the plane. But while modern airplanes do have the ability to reverse on their own, they often choose not to.
In this article, we will be covering how airplanes reverse in order to taxi. We will also discuss why it is that even though they have the ability to reverse on their own, they choose to use the assistance of some ground vehicle to achieve this. We will start by looking into how airplanes can reverse on their own.
How can airplanes reverse on their own?
While airplanes do not have the reverse gear as your typical ground vehicle like a car or a truck would have, they do use a mechanism known as Powerback system to reverse on their own. While this isn’t the preferred option for an airplane to reverse, they will use it when there are no other options, and when they absolutely have to.
So how exactly does the Powerback system work?
This system employs what is known as Reverse Thrust to help reverse the airplane. The reverse thrust is activated when the jet engines that the planes normally use to move forward is used in a reverse direction.
Normally, a jet engine expels gas from its back at high speed. The plane’s fuel is burned using the oxygen from the air, and this, in turn, turns the engine’s turbine. The turbine takes in air from the front and expels it at a high velocity from the back. And by Newton’s third law (to every action, there is an equal and opposite reaction), a forward thrust is generated, which helps the plane move forward.
Reverse thrust
Reverse thrust operates in the exact opposite way. Instead of the air being pushed backward at high speed, the direction is changed, making it flow forward. Thus, once again, by Newton’s third law of motion, the plane experiences a backward force.
Pilots don’t usually employ reverse thrust to reverse a plane in order to taxi. Rather, the normal use of this mechanism is to slow the plane down before landing. Pilots cannot use reverse thrust to reverse the plane while it is in flight.
However, the backward force can help decelerate the plane, thus making it easier to land on a runway. Pilots will engage this feature just before they approach the landing phase, so as to slow the speed of the plane down to an appropriate number. After the tires of the plane hit the ground, however, the brakes play the biggest role in slowing the plane down until it comes to a complete halt.
While smaller planes have the ability to completely reverse the flow of air, larger planes can only achieve this partially. And you may find smaller planes using reverse thrust to reverse on their own, bigger planes avoid using this feature when they can.
Instead, they use the assistance of special ground vehicles known as pushback tractors that use a tow bar to hook up to the nose wheel of the airplane. They can then proceed on to push and pull the plane into place in order to help them taxi.
Why don’t airplanes reverse on their own?
So why is it that despite having the ability to reverse on their own, planes choose to use a ground vehicle to help them reverse?
The short answer is, a tug from a ground vehicle is much cheaper than using the plane’s own reverse thrust. There are five main disadvantages to using the reverse thrust over a pushback tractor to back an airplane:
1.Reverse thrust consumes more fuel
Reverse thrust consumes a lot more fuel compared to a pushback tractor. The reverse thrust feature will actually only be effective in reversing the plane when it is turned on high. This will consume a lot of fuel, which makes the process economically inefficient.
2.Higher fuel consumption costs more money and is worse for the environment
Higher fuel consumption is not only economically inefficient, but it is also bad for the environment. An airplane on reverse thrust will release a lot more carbon dioxide in the air compared to a pushback tractor.
3.Reverse thrust is extremely loud
The jet engine of an airplane produces a lot of noise. And this is especially true when it employs reverse thrust, as the feature will only be effective on higher levels. This can be rather disconcerting for all the airport staff as well as the passengers on board and around at the airport.
4.Reverse thrust is dangerous to ground personnel
A jet engine on reverse thrust can be extremely dangerous to ground personnel standing nearby. Since it releases a lot of air in high velocity, this can blow the people standing nearby. Additionally, it can also blow dirt and other debris around. Hence using reverse thrust to back an airplane can give rise to safety issues.
5.Reverse thrust can harm the engine
Finally, using reverse thrust on the ground can also be harmful to the engine. While there are very little dirt and debris on air where the jet engine of the plane usually operates, this isn’t true for the airport ground. There are a lot of tiny objects that can blow into the engine, damaging it or at least adding to its wear and tear.
So there you have it—five reasons why it isn’t efficient for airplanes to reverse on their own.
Pilots do use reverse thrust on a regular basis. But it is usually only used to decelerate the plane to an appropriate speed so that it can be landed on a runway. Once the plane has landed, it is extremely rare for pilots to employ reverse thrust to back the airplane. There are numerous downsides to employing this mechanism, and pilots typically avoid it unless they have no other option.
Conclusion
While most modern airplanes do have the ability to reverse on their own, they choose not to. For them to do so, airplanes use a special mechanism known as reverse thrust. This is when the jet engine that the plane normally uses to move forward reverses its function, pushing the air out from the front, thus generating a backward force.
But planes only use reverse thrust to decelerate the plane, and seldom use it to reverse on the ground after landing. Instead, they use a pushback tractor that hooks up to their nose wheel and tugs them into place in order to taxi.
There are a few reasons why planes avoid using their reverse thrust feature to taxi on their own. Firstly, the use of reverse thrust generates a lot of noise. This can be disconcerting for the airport staff as well as the other passengers on the plane and nearby.
Using a pushback tractor is a lot quieter. The air that the engine produces when on reverse thrust can also be dangerous for the people standing nearby. Finally, the environmental cost can be worse with reverse thrust as well. This feature produces a lot more carbon dioxide compared to the minuscule amount produced by the pushback tractor.
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