Dutch roll

This yaw-roll coupling is one of the basic flight dynamic modes (others include phugoid, short period, and spiral divergence).

This motion is normally well damped in most light aircraft, though some aircraft with well-damped Dutch roll modes can experience a degradation in damping as airspeed decreases and altitude increases.

Dutch roll stability can be artificially increased by the installation of a yaw damper.

Strong lateral stability (due to the more-direct airflow past the down wing, which has been pivoted forward by the slip) begins to restore the aircraft to level flight.

At the same time, somewhat weaker directional stability (due both to greater drag from the wing which is now generating greater lift, and by aerodynamic force on the vertical fin due to the yaw) attempts to correct the sideslip by aligning the aircraft with the perceived relative wind.

The aircraft passes through level flight as the yawing motion is continuing in the direction of the original roll.

At that point, the sideslip is introduced in the opposite direction and the process is reversed.

[1] The most common mechanism of Dutch roll occurrence is a yawing motion which can be caused by a number of factors.

[citation needed] Tex Johnston describes the Dutch roll as "...an inherent characteristic of swept-wing aircraft.

"[2] Dutch roll is also the name (considered by professionals to be a misnomer) given to a coordination maneuver generally taught to student pilots to improve their "stick-and-rudder" technique.