With one SFCC inoperative, the flaps

With one SFCC inoperative, the flaps

• A. Operate normally
• B. Operate at half speed
• C. Do not move
• D. Fully retract

Answer: (B)

When a system has dual-channel redundancy, such as the flap/slat control, losing one channel means the remaining channel takes over in a degraded mode. In this degraded state, the flaps are not commanded at their normal full-rate speed; instead, the active SFCC drives them at half speed. This slower movement reduces dynamic loads, lowers the risk of mechanical clash or control issues, and gives the crew time to manage the situation safely. So, with one SFCC inoperative, the flaps operate at half speed to maintain controlled, safe extension and retraction rather than moving normally or staying fixed, and certainly not fully retracting by default.

When a system has dual-channel redundancy, such as the flap/slat control, losing one channel means the remaining channel takes over in a degraded mode. In this degraded state, the flaps are not commanded at their normal full-rate speed; instead, the active SFCC drives them at half speed. This slower movement reduces dynamic loads, lowers the risk of mechanical clash or control issues, and gives the crew time to manage the situation safely.

So, with one SFCC inoperative, the flaps operate at half speed to maintain controlled, safe extension and retraction rather than moving normally or staying fixed, and certainly not fully retracting by default.