What position does the emergency flap switch command the slats/flaps?

What position does the emergency flap switch command the slats/flaps?

• A. 0 degrees
• B. 10 degrees
• C. 20 degrees
• D. 30 degrees

Answer: (C)

Emergency extension uses a fixed position to ensure lift is available when the normal flap system isn’t working. The switch commands the flaps/slats to a preset of twenty degrees, a setting chosen to provide enough lift for a safe approach at low speed while keeping drag at a manageable level. This consistent 20-degree position is reliable in degraded hydraulics scenarios, so you still have controllable authority during an emergency. Compared to 0 degrees, there’s no extra lift; compared to 10 degrees, you don’t get enough lift; and 30 degrees would overextend and add unnecessary drag without additional benefit in this backup mode.

Emergency extension uses a fixed position to ensure lift is available when the normal flap system isn’t working. The switch commands the flaps/slats to a preset of twenty degrees, a setting chosen to provide enough lift for a safe approach at low speed while keeping drag at a manageable level. This consistent 20-degree position is reliable in degraded hydraulics scenarios, so you still have controllable authority during an emergency. Compared to 0 degrees, there’s no extra lift; compared to 10 degrees, you don’t get enough lift; and 30 degrees would overextend and add unnecessary drag without additional benefit in this backup mode.