# Turn Indicator and Turn Coordinator: Rate-1 Turns, Slip, and Skid

> Understand turn-indication instruments, including turn-rate sensing, Rate-1 turns, and slip/skid coordination with the inclinometer ball.

- **Subject:** 022 — Instrumentation
- **Section:** 022-04 — Gyroscopic Instruments
- **Topic code:** 022-04-02
- **Last reviewed:** 2026-03-27
- **Author:** Pablo Asensio Martínez
- **HTML version:** https://pilotsyllabus.com/en/instrumentation/gyroscopic-instruments/rate-of-turn-indicator-turn-coordinator-balance-slip-indicator/

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These instruments indicate the **rate** of turn (yaw) and the quality of the turn (coordination).

## Turn Indicator vs. Turn Coordinator
1.  **Turn Indicator (Turn and Slip):**
    *   **Gyro:** Horizontal axis, 1 degree of freedom (Gimbal frame).
    *   **Sensitive to:** **YAW only**.
    *   **Display:** A "needle" or "bat" indicates the rate of turn.
2.  **Turn Coordinator:**
    *   **Gyro:** The gimbal is canted (angled) at **30°** to the longitudinal axis.
    *   **Sensitive to:** **ROLL and YAW**. It reacts faster to the start of a turn (roll) but stabilizes to show rate of yaw.
    *   **Display:** An aircraft symbol banks to show the rate of turn.

## Rate 1 Turn (Standard Rate)
*   **Definition:** A turn rate of **3° per second**.
*   **360° Turn:** Takes **2 minutes**.
*   **Rule of Thumb for Bank Angle:** $\text{Bank Angle} \approx \frac{TAS}{10} + 7$.
    *   Example: At 120 kts TAS, Bank $\approx 12 + 7 = 19^\circ$.

## Balance (Slip) Indicator
Consists of a ball in a fluid-filled curved tube (inclinometer). It indicates the coordination of the turn (Balance of Centrifugal Force vs. Gravity/Weight).
*   **Ball Centered:** Coordinated turn.
*   **Ball Inside turn (Same side):** **Slip** (Not enough bank for the rate of turn, or too much rudder into the turn).
*   **Ball Outside turn (Opposite side):** **Skid** (Too much bank, or too much opposite rudder).
*   *Mnemonic:* "Step on the ball" to center it.

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Free study notes from pilotsyllabus.com. Not a substitute for training at an approved ATO.