What makes the Propeller Feathered when the engine fails?

• A. TSS
• B. Hydraulic pressure
• C. Pitch lock
• D. N1 fault

Answer: (A)

Feathering reduces drag by turning the propeller blades to a high-pitch angle so they slice through the air with minimal resistance when an engine fails. The automatic feathering action is triggered by the TSS when a power loss is detected. Once activated, hydraulic pressure is directed to the propeller’s pitch-change mechanism, moving the blades into the feathered position and holding them there. This rapid change helps maintain controllability and climb performance after an engine failure. If the TSS didn’t act, the blades might stay in the normal flight pitch, creating excessive drag. The other options describe components or fault modes related to the system, but the automatic feathering on engine failure is governed by the TSS.