Turn Coordinator vs Turn Indicator

Turn Indicator: Function and Indication

A turn indicator, sometimes called a turn and slip indicator, is a gyroscopic instrument that displays the rate at which the aircraft is changing heading (yaw rate). It uses a single gimbal gyroscope with its axis aligned horizontally and parallel to the aircraft’s lateral (pitch) axis. The instrument’s needle or pointer moves in response to yaw, showing the rate of turn—most commonly calibrated for a 'rate 1 turn' (3° per second, or a full 360° in 2 minutes). It does not respond to roll; only established yaw produces a reading.

Paired with the turn indicator is a balance (slip) indicator—a ball in a curved tube—which shows whether the turn is coordinated, slipping, or skidding. A centered ball means a balanced turn; displacement left or right signals a slip or skid.

Turn Coordinator: Enhanced Sensitivity

The turn coordinator improves upon the basic turn indicator by tilting the gyroscope’s gimbal 30° forward. This modification allows the instrument to sense both yaw and roll rates. As soon as the aircraft starts banking, the turn coordinator’s miniature airplane symbol begins to move, providing immediate feedback that a turn is commencing—even before a steady yaw rate is established. Once the turn stabilizes, the instrument behaves like a standard turn indicator, showing yaw rate only.

However, the turn coordinator’s accuracy for rate 1 turns is best within a narrow speed range (close to its calibration speed). At higher or lower speeds, the rate indication may become less reliable. The instrument’s display often resembles an artificial horizon, but it provides no pitch information—a fact emphasized by a warning label.

Key Differences

• Sensitivity: Turn indicator responds only to yaw; turn coordinator responds to both roll and yaw.
• Turn Entry: Turn coordinator shows turn entry as soon as roll begins; turn indicator reacts only after yaw is established.
• Calibration: Both are accurate for rate 1 turns only near their design airspeed.
• Display: Turn coordinator uses a miniature airplane, which can be confused with the artificial horizon under stress.

Slip/Skid Indication

Both instruments are paired with a balance ball to indicate turn coordination. The ball’s position tells the pilot if the turn is balanced, slipping, or skidding, essential for safe and efficient maneuvering.