How many Feather Inhibit shutdowns require a normal shutdown?

• A. 3
• B. 5
• C. 7
• D. 9

Answer: (D)

Feather Inhibit is a protective feature in the PC-12 NGX’s prop/engine control. When a feather inhibit shutdown occurs, it signals a fault that prevents the prop from feathering and keeps the engine in a safe, non-feathered state. The system is counting these inhibit events, and after a certain number of such events, a normal shutdown is required to reset the protective logic and ensure the engine/prop system is brought down in a controlled, verifiable state.

Reaching the threshold means repeated inhibit conditions suggest the fault isn’t clearing, so performing a normal shutdown helps reinitialize systems, clear the inhibit condition, and allow proper fault isolation during post-flight checks. The nine-event threshold balances safety with practicality, avoiding premature restarts while ensuring a safe, definitive shutdown when the fault persists.