What characterizes Dutch roll?

Dutch roll is characterized by oscillatory instability that involves simultaneous yawing and rolling motions of an aircraft. This phenomenon arises primarily due to the aerodynamic interactions between the aircraft's lateral stability and the yawing moment resulting from adverse yaw. When an aircraft experiences a yawing motion, such as when it is rolled into a turn, it can create a tendency for the nose to move away from the intended flight path. As it begins to yaw, the wing on the outside of the turn generates more lift and can roll the aircraft in the opposite direction, initiating an oscillation.

These oscillations can persist due to the aircraft's inherent design features, such as the relative position of the center of gravity and the wings' aerodynamic characteristics. As a result, the aircraft may go through a series of alternating yaw and roll movements, creating a significant challenge for pilots if not properly managed.

The other options do not accurately capture the essence of Dutch roll. For instance, stable flight with little motion describes a well-controlled aircraft not experiencing any destabilizing forces, while uncontrolled descent with rapid yaw does not reflect the defined oscillatory nature of Dutch roll. Lastly, constant altitude with no lateral motion signifies a different aerodynamic condition where the aircraft is not facing any instabilities.