What mechanism does the turn coordinator use to indicate the direction of a turn?

The turn coordinator indicates the direction of a turn primarily through the principle of precession, which is a property of gyroscopes. When the aircraft initiates a turn, the gyroscope inside the turn coordinator experiences a force due to the aircraft's rotation. This force causes the axis of the gyroscope to tilt in a direction that is 90 degrees ahead of the turn's actual heading.

As a result, the turn coordinator shows the direction of the turn—whether left or right—based on how the gyro precesses in response to the aircraft's movement. This provides a visual indication to the pilot, aiding in maintaining the desired flight path and ensuring that the turn is properly coordinated.

Understanding precession is essential for pilots since it contributes to effective maneuvering and safe flying practices, especially in scenarios where precise turns are necessary.