Turn Coordinator

Click on the turn coordinator to watch the movie.

The turn coordinator is really two instruments. The gyro portion shows the aircraft's rate of turn—how fast it's changing direction. A ball in a tube called the "inclinometer" or "slip/skid indicator" shows the quality of the turn—whether the turn is "coordinated."

How It Works

The gyro in the turn coordinator is usually mounted at a 30-degree angle. When the airplane turns, forces cause the gyro to precess. The rate of precession makes a miniature airplane on the face of the instrument bank left or right. The faster the turn, the greater the precession, and the steeper the bank of the miniature airplane.

Standard Rate Turn

When the wings of the miniature airplane align with the small lines next to the "L" and "R," the aircraft is making a standard rate turn, which in the Cessna 182RG is three degrees per second. This means the aircraft completes a 360-degree turn in two minutes.

Balancing Act

The black ball in the slip/skid indicator stays between the two vertical reference lines when the forces in a turn are balanced and the airplane is in coordinated flight. If the ball drops toward the inside of the turn, the airplane is slipping. If the ball moves toward the outside of the turn, the airplane is skidding.

To correct a skid, reduce rudder pressure being held in the direction of the turn and/or increase the bank angle.

To correct a slip, add rudder pressure in the direction of the turn and/or decrease the bank angle.The auto-coordination feature in Flight Simulator automatically moves the rudder to maintain coordinated flight.

Useful Backup

The turn coordinator is usually electrically powered so that it's available if the vacuum pump fails and disables the attitude indicator and heading indicator.

Needle and Ball

The turn coordinator is common in modern light aircraft such as the Cessna 182RG. Older airplanes often have a similar instrument called the "turn and slip indicator" or the "needle and ball," which uses a different presentation to display the same information.