Refer to figure.

Τurn and bank Coordinator displays the Rate of Turn as well as Roll information and is used to determine the coordination of a Turn (e.g., slipping or skidding) and the bank angle required for a specific Rate of Turn (e.g., 2 minutes for 360 degrees). The Turn Indicator is a gyroscopic instrument that works on the principle of precession.

The Slip/Skid Indicator (Inclinometer) is used to depict aircraft yaw (directional stability), which is the side-to-side movement of the aircraft’s nose. During coordinated, straight-and-level flight, the force of gravity causes the ball to rest in the lowest part of the tube, centered between the reference lines. Coordinated flight is maintained by keeping the ball centered. If the ball is not centered, it can be centered by using the rudder.

To center the ball, apply rudder pressure on the side to which the ball is deflected. Use the simple rule, “step on the ball,” to remember which rudder pedal to press. If the aileron and rudder are coordinated during a turn, the ball remains centered in the tube. If aerodynamic forces are unbalanced, the ball moves away from the center of the tube.

In a slip, the rate of turn is too slow for the angle of bank, and the ball moves to the inside of the turn. In a skid, the rate of turn is too great for the angle of bank, and the ball moves to the outside of the turn.

To correct for these conditions, and improve the quality of the turn, remember to “step on the ball.” Varying the angle of bank, can also help restore coordinated flight from a slip or skid.

To correct for a slip, decrease bank and/or increase the rate of turn. To correct for a skid, increase the bank and/or decrease the rate of turn.

A Turn and Bank (or Turn and Slip) Coordinator provides information regarding for the Rate of Turn and Coordination, i.e. Slip or Skid, of the turn.