Skid (aerodynamics)

In a straight flight, the tail of the airplane aligns the fuselage into the relative wind.

But during the final approach, when the airplane is close to the ground, a stall-spin accident is often fatal.

By balancing the roll's turn to the right with the rudder's yaw to the left, the plane continues to fly straight ahead but it presents its side rather than its nose to the airstream.

The drag from this aerodynamically "dirty", clumsy position slows the otherwise sleek airplane.

Thus the plane can be slowed quickly in level flight or the descent to a landing can be dramatically steepened while holding the approach speed to a desired value.