An 'Auto - Feathering' system primarily senses which condition?

The 'Auto- Feathering' system is an important mechanism in certain aircraft engines, particularly those driven by turboprop engines. Its primary function revolves around optimizing the performance of the propeller in flight. When the system detects low torque, it is an indication that the engine is not producing enough power to sustain the desired operational capabilities.

Specifically, this situation often arises in scenarios such as engine failure or significant reductions in throttle settings. In these cases, the auto-feathering system automatically adjusts the pitch of the propeller blades, typically moving them to a feathered position. This adjustment minimizes drag and allows the aircraft to maintain better performance and control, even with a non-operational engine.

The ability to sense low torque is crucial as it allows for timely intervention by the system to prevent a loss of control or excessive drag during flight. Therefore, the condition of low torque is the key input that triggers the auto-feathering system to engage.