FAA Powerplant Written Practice Test

What type of control would the FADEC system replace in many turbine engines?

1. Analog mechanical control

2. Simple manual control

3. Hydro mechanical control

4. Fluid dynamic control

The correct answer is: Hydro mechanical control

The FADEC (Full Authority Digital Engine Control) system is designed to enhance the performance, efficiency, and reliability of turbine engines. By utilizing digital technology, the FADEC system can replace hydro mechanical control systems, which traditionally relied on mechanical linkages and hydraulic actuators to manage engine parameters like fuel flow, ignition, and variable geometry components. Hydro mechanical control systems are more limited in their adaptability and responsiveness when compared to FADEC systems. The digital nature of FADEC allows for real-time adjustments based on a wide range of flight conditions, optimizing engine performance in a way that hydro mechanical systems cannot achieve. FADEC can process various inputs from sensors faster and more accurately, allowing for improved efficiency and performance, greater fuel economy, and reduced emissions. In contrast, while analog mechanical controls and simple manual controls exist within some older or less sophisticated systems, they do not provide the same level of automation, precision, and integration as what FADEC offers. Fluid dynamic control is also not a direct competitor in the same realm as hydro mechanical control, as it refers more to the principles of operation rather than the specific control schemes utilized in turbine engines. Thus, the FADEC system predominantly replaces hydro mechanical control systems for enhanced engine management.