What is the function of the turn coordinator and what does a slip/skid indicate?

• A. It shows airspeed; slip/skid indicates turbulence.
• B. It shows rate of turn and quality of the turn; slip or skid indicates uncoordinated flight.
• C. It shows altitude; slip/skid indicates engine failure.
• D. It shows bank angle; slip/skid indicates heading error.

Answer: (B)

Turn coordinator tells you how fast you’re turning and whether that turn is coordinated with the rudder. Its gyroscope is mounted at a tilt, so it senses both yaw (rate of turn) and roll (how you’re entering or holding the turn). The little airplane on the indicator tilts to show the rate of turn, and you’ll typically use it to dial in standard-rate turns (3 degrees per second).

The slip/skid indicator is the ball in the curved tube. It shows coordination between the turn and the rudder: when the ball is centered, the flight is coordinated; if the ball moves to one side, the aircraft is slipping or skidding (uncoordinated), which means you need to adjust rudder and bank to bring it back to coordinated flight.