What Is Dutch Roll?

Deep in the pages of the aerodynamics manual, you come across some of those big things that you don’t think about too much when flying little planes. One of those things is Dutch roll, the out-of-phase oscillations that can cause big problems for some swept-wing jets.  

So, if you’re wondering what is Dutch Roll, here’s a deep dive into what it is, its effects, what causes it, and what to do about it.

Dutch Roll Defined

Dutch roll is a side-to-side oscillation of an aircraft where the wings roll in one direction while the nose yaws in the opposite direction, creating an unstable motion pattern.

Swept-wing designs, typical of modern jets, are the most common type of airplane to have problems with Dutch roll. 

It’s caused by the forces designed to keep an airplane stable around the airplane axes, like the sweep of the wings and the keel effect (the tendency of the plane to remain flying straight ahead). 

In the case of Dutch roll, once a wing dips, the righting motions of these design features kick in to return it to straight and level flight.

But, because the corrective forces differ in effectiveness, an oscillation develops.

The nose of the plane draws a figure eight across the sky. If you were outside the plane, it might look like it was wagging its tail while rolling its wings. 

The amount of Dutch roll differs from aircraft to aircraft and from one flight regime to another.

What Are the Effects of Dutch Roll?

Dutch roll is a specific result of a combination of stability forces acting on the plane.

The problem is that the different stability forces occur in differing amounts, thereby setting up an oscillation that could be weak, barely noticeable, or strong enough to damage the aircraft.

The amount experienced depends on the plane type, its flight regime, and the corrective actions the pilot takes. 

Dutch roll is most dangerous in fast aircraft with swept wings.

To reduce this tendency, these planes sometimes require an automatic yaw damper. Severe Dutch roll oscillations exceeding the aircraft’s load limits have caused several accidents. 

In 2024, a Southwest Boeing 737 MAX 8 made the news when the aircraft experienced a Dutch roll incident on a flight from Phoenix to Oakland. While the event wasn’t serious, it was scrutinized due to the public’s safety concerns with the 737 MAX. 

Forces Behind Dutch Roll

Airplanes incorporate numerous design elements that keep them stable during flight.

Stability is defined in two ways: static and dynamic.

Static Stability

Static stability is how easily a plane is disturbed from its flight path. You can visualize static stability by imagining a plane flying through turbulence during straight and level flight at altitude. If the plane has positive static stability, the turbulence will not affect its flight path. 

However, if a plane has too much stability, it will be difficult to control because even the controls would have trouble overcoming such a force. Aircraft designers must balance stability with controllability and maneuverability.

Dynamic Stability

Dynamic stability is the tendency of an aircraft to return to its original flight path if disturbed. In the example above, if the turbulence caused the plane to veer into a banked turn, dynamic stability would help it return to straight and level flight.

All stability can be described as positive, neutral, or negative. Negative stability means that once a plane is disturbed from its flight path, the disturbance keeps getting worse. This might sound like a bad thing, but many planes are designed to be negatively stable to facilitate easier control. Aerobatic planes, for example, exchange stability for maneuverability. 

Once you understand the basics of stability and controllability, you can start looking for aircraft design features that aim to harness it. Common things you see are wing dihedral and the weathervane effect of the rudder effect. 

The sweepback of wings on high-speed airplanes can also provide a factor of stability. When the plane yaws one way, one wing gains angle of attack, producing more lift to correct the yaw.

However, the increased lift also produces more induced drag, which exacerbates the yawing. 

How Do You Correct Dutch Roll?

While any aircraft can experience a Dutch roll, most of them self-correct quickly.

When they don’t, a bit of rudder input from the pilot will fix the problem. This describes nearly all light aircraft. 

A yaw damper will be fitted if a design tends to stabilize in a Dutch roll, enters it too quickly, or worsens over time.

The yaw damper is an autopilot system that quickly applies a small amount of rudder, stopping the oscillations and the Dutch roll. Often these engage before the pilot even notices the Dutch roll.

How to Correct Dutch Roll in Flight

Here are some basic steps to correct Dutch roll while flying if your aircraft doesn’t have an autopilot system to do it.

• Assess the Severity – If the oscillation is minor, it may naturally dampen out without pilot input. Observe the motion before reacting.
• Use Rudder, Not Ailerons – Aileron inputs can make the oscillations worse. Use the rudder to counteract the yawing motion.
• Apply Small, Smooth Rudder Inputs – Gently apply rudder in the direction opposite to the yaw, but avoid overcorrection. Large or aggressive inputs can amplify the oscillation.
• Avoid Chasing the Motion – Trying to “catch up” with Dutch roll by making constant adjustments can worsen the instability. Instead, apply a steady correction and let the aircraft stabilize.
• Verify Yaw Damper Status – In aircraft equipped with a yaw damper, ensure it is engaged. If it’s inoperative or disengaged, manual rudder inputs will be required.
• Maintain Situational Awareness – If the Dutch roll is severe and continues to worsen despite corrective action, consider reducing airspeed within safe limits to help stabilize the aircraft.

Who Needs a Yaw Damper?

Most transport category aircraft built today have yaw dampers.

If a plane has particularly bad Dutch roll tendencies, the yaw damper may be required equipment.

The 727 had a famously bad Dutch roll tendency due to the swept wings and T-tail empennage. The yaw damper was critical to flight on this plane, so it had two on board: one for the upper rudder and one for the lower. 

But not all planes, even those with swept wings, need yaw dampers.

Many designs have them fitted simply because they accomplish the job quicker than pilots can and provide a smoother ride for passengers. 

Some small planes have yaw dampers for this reason, too.

The Cirrus SR-22 has one that turns on automatically after takeoff and then off before landing. It’s part of the autopilot but runs constantly unless specifically switched off. 

Yaw dampers work by applying the rudder for the pilot.

In most planes with yaw dampers, rudder inputs are not necessary. They are kept off during takeoff and landing since the pilot wants the ability to use sideslips to handle crosswinds.

A yaw damper could also mask the telltale control forces that would indicate a failed engine in a multi-engine aircraft. 

Dutch Roll is described in Chapter 5: Aerodynamics of Flight of the FAA Pilot’s Handbook of Aeronautical Knowledge.