From where do the IGVs receive their controlling signal?

The control of the Inlet Guide Vanes (IGVs) in a turbine engine is predominantly managed by the Fuel Control Unit (FCU). As the primary component responsible for regulating the fuel flow into the combustion chamber, the FCU processes various engine parameters to ensure optimal performance and efficiency.

When the FCU receives inputs from other engine sensors—such as those measuring engine speed and temperature—it can adjust the fuel flow accordingly. This adjustment not only affects the combustion process but also influences the position of the IGVs. The IGVs are crucial for managing airflow into the engine at different operating conditions, helping to enhance performance and efficiency. By receiving signals from the FCU, the IGVs can open or close appropriately based on the current demand for thrust, ensuring the engine operates efficiently across various flight conditions.

While electronic control modules and hydraulic systems play roles in the overall control mechanisms of modern engines, they typically interface with or support the FCU rather than serve as the primary source for controlling the IGVs directly. The engine speed sensor contributes vital data used by the FCU, but it does not control the IGVs on its own. Understanding this hierarchy is essential for grasping how different systems within the turbine engine interact and work cohesively.