How Airplane Rudders Work

Rudders are an essential yet often misunderstood component of the flight control system, playing an important role in safely transporting passengers and cargo across the skies. 

Here are some of the most common questions asked about airplane rudders:

What Controls the Rudder On a Plane?

On the vast majority of aircraft, the rudder is controlled by foot pedals in the cockpit. Pushing the left pedal deflects the rudder to the left and vice versa. Smaller, private planes generally control the rudder using pedals, while larger planes typically use hydraulic actuators. When rudders are powered by hydraulics, they can shift in the direction the wind blows once the plane has landed and the power is off.

Just like the image above, you may have noticed the rudders on airliners turned slightly at an angle when they are parked at the gate. Sophisticated, more modern planes also limit the rudder travel when the plane is going faster (the faster the plane, the less rudder movement is required). 

A few small planes have alternative rudder controls. For example, the Ercoupe is flown using only a control wheel with the rudder and aileron systems linked. However, this is not standard.

Can You Turn an Airplane With Just the Rudder?

In short, no; if you just use a plane’s rudder, only the nose of the plane will turn slightly. You cannot make significant turns with the rudder alone. The rudder only controls the yaw, which is the vertical axis of the plane. Pilots need to also use the aileron and elevator as well. In contrast, boats use the rudder as their primary method of control for maneuvering.

So, Does The Rudder Control Pitch?

No. Pitch, which refers to the lateral axis of the plane, is controlled by the elevators. And as you may have guessed, the elevators are named so because they move up and down depending on the direction of the control stick.

Can a Plane Turn Without Using the Rudder?

Yes, although it may be a bit messy. As mentioned, the rudder is not used to turn the plane, its purpose is to control the nose of the plane. A plane can successfully turn without a rudder, however, it can result in adverse yaw, where the nose turns momentarily away from the direction of travel, making it harder to control.

How Does the Rudder Control Yaw?

At the rear of most airplanes is a vertical stabilizer which is directly part of the tail. This stabilizer helps prevent inadvertent side-to-side motion (called yawing) which would otherwise make for uncomfortable and potentially dangerous flights. The rudder is a flight control surface that is attached to the rear of the stabilizer with simple hinges.

Planes turn by banking and using the ailerons or spoilers on the wing. The rudder will help to control that turn by changing the shape of the vertical stabilizer, preventing the nose from slipping out of the turn. It’s all about aerodynamics.

This also allows for a slip or sideslip maneuver, in which the plane moves forward and sideways at the same time, which pilots use to compensate for crosswind conditions when landing. It’s also used to rapidly reduce altitude by creating drag. This can result in a spectacularly hard landing.

Can a Plane Fly Without a Rudder?

Most modern planes can fly and safely land without a rudder. In fact, in 1989 a British Airways Concorde lost part of its rudder, and the damage was not noticed until the plane was on the ground. You can read the entire investigation report from the British government here if you’re looking for a bit of light reading before bed. As so often happens with aircraft incidents, whether catastrophic or not, the accident was investigated and found to be an issue from improper maintenance to the outer skin of the rudder.

In most cases, if damage to the rudder is minimal it is not an immediate emergency and most planes can be adequately controlled using just the ailerons and elevators. However, severe damage to the rudder can cause catastrophic accidents for a plane.

Is It Possible to Overuse the Rudder?

As mentioned, the majority of modern planes only require a slight amount of rudder be applied to help control the yaw. If a rudder is used too much in a short period of time, or held for too long, it can result in structural damage to the tail of the plane.

Which is unfortunately what happened on November 12th, 2001, when an Airbus A300-305R crashed after its tail came apart, killing all 260 people on the plane and five people on the ground. The investigation found it to be caused by too much stress on the rudder when the pilot tried to compensate for another plane’s wake. As a result, aircraft are required to have warning lights for excessive use of rudders. Although many believe this issue can be handled by better rudder training for pilots.

Why Don’t Birds Need Rudders?

Birds obviously don’t have rudders or vertical stabilizers. But why don’t they need them? To put it bluntly, birds have evolved to become much smarter than airplanes. Or at least, birds are designed for a much wider variety of conditions. Their control surfaces are much more adaptable and flexible, and one small change in the wing can affect yaw, pitch and roll all at once. No heavy engine weighs them down in their belly and their brains can relay their commands much faster than our onboard computers.

Birds also don’t lose engines…if they are too sore to fly, they don’t fly. Aside from Albatrosses, no birds have to utilize any kind of runway for take off or landing, which means if they are trying to touch down in a cross wind, they will simply turn into the wind and glide to the ground.

They do, of course, have a tail that can serve some of the same purposes as a plane’s vertical stabilizer. All joking aside, any flying enthusiast should look more into the mechanics of avian flight; while incredible, there are no birds anywhere near capable of the feats of speed and lifting technology that modern aircraft are capable of. 

What Is The Impact of Rudders at High Speeds?

As already mentioned, the faster the plane is traveling, the less the rudder needs to move to be effective. One of the reasons why the famous rudder problem on the Concorde was not noticed was that at supersonic and hypersonic speeds, the rudder actually becomes inefficient. Supersonic planes thus do not make much use of the rudder to turn.

Some fighter jets actually have twin rudders (as do some civilian aircraft), which help them stay stable during tight turns and compensate for the greater power of the engines and the smaller size of the plane. It also allows for more control during slower speeds or when landing.

Notice how the older Slovakian jet below utilizes a twin rudder design for some of these valuable trade-offs in maneuverability over speed.

Whereas the more modern design below leverages a single rudder within its design.

As with all decisions related to engineering and aviation there are trade-offs that are typically impacted by needs at the time and intended use of the aircraft in the skies.

Are Rudders Easily Fixed?

Given how important rudders are for the control stability of most planes, you need to fix damage to a rudder as quickly as possible. There are two common repairs. One is reskinning, where the outer skin of the rudder is replaced. If the rudder is more seriously damaged, it may have to be replaced. This can be a challenge if you are flying an older plane. If you are unable to purchase one brand new, trying to find one secondhand may be your only option.

This is where PartsBase comes in. We are the world’s largest network of aviation parts and services and can help you get flying again faster. Schedule a free demo today to find out how we can help you find the right (and safest) parts for your plane, or search our aircraft parts database directly to find what you need.