During flight, how would you identify a potential failure of the turn coordinator vs the turn indicator?

• A. Compare indications from the turn coordinator and turn indicator with AI cross-check.
• B. Rely on the turn indicator only.
• C. Use magnetic compass for orientation.
• D. Trust ATC instruction.

Answer: (A)

Cross-checking instruments is how you spot a turn-rate instrument failure. The turn coordinator is tilted so it senses both roll and yaw, giving quick feedback as you roll into a turn, while the turn indicator primarily reads yaw rate. In coordinated flight, the two should show a consistent rate of turn that matches what the attitude indicator shows about the aircraft’s bank. If one instrument shows a turn and the other doesn’t, or if their readings don’t align with the attitude indicator’s bank, you have a likely fault in one of the turn instruments. By comparing both turn indicators with the attitude indicator (AI cross-check), you can identify the discrepancy and know which instrument to trust or treat as unreliable. Relying on a single instrument, using a magnetic compass for turn rate, or following ATC instructions alone won’t reliably reveal an instrument failure.