Purpose of and procedures for forward or side slip to a landing.

Bottom line

Assuming the airplane is originally in straight coordinated flight, a slip lowers the wing on one side with ailerons while sufficient opposite rudder yaws the nose so the airplane remains on its original flightpath. In a forward slip, the amount of slip and therefore the sink rate is determined by the bank angle: the steeper the bank, the steeper the descent. Airspeed indicators in some airplanes may have considerable error during a slip, so the pilot needs to recognize a proper slip by the attitude of the airplane, the sound of the airflow, and the feel of the flight controls.