Which safety feature provides autofeathering when an engine fails in a turboprop?

• A. FADEC
• B. Autoignition system
• C. TSS
• D. Hydraulic lock system

Answer: (C)

Autofeathering is a safety action that happens when an engine in a turboprop fails or loses significant power. It automatically moves the propeller blades to the feather angle, turning them nearly parallel to the airflow. This greatly reduces windmilling drag and helps keep the aircraft controllable and easier to fly on one engine.

The system that performs this automatic response is the TSS. It monitors the engine’s condition and, if it detects a failure or abnormal torque/power, it actuates the propeller control to feather without pilot input. This automatic reaction is crucial for maintaining directional stability and reducing the workload during an engine-out scenario.

FADEC does control engine and propeller parameters and can influence how the engine and propeller cooperate, but the explicit safety feature that automatically feathers the propeller on engine failure is the TSS. The other options don’t relate to feathering: autoignition concerns ignition timing, hydraulic lock relates to hydraulic systems, and neither provides the automatic feathering function.