FAA Powerplant Written Practice Test

What distinguishes Full Authority Digital Engine Control (FADEC) from other systems?

1. It has a mechanical backup for fuel control

2. It has no hydro mechanical fuel control backup

3. It requires more pilot input to operate

4. It is limited to basic engine management

The correct answer is: It has no hydro mechanical fuel control backup

Full Authority Digital Engine Control (FADEC) is distinguished by its design, which completely integrates digital control of the engine's operating parameters without relying on hydro-mechanical systems for backup. This means that FADEC systems do not have an auxiliary mechanical means for fuel control; instead, they utilize electronic control for optimizing engine performance. This lack of hydro-mechanical backup allows FADEC to manage the engine more precisely and efficiently, leading to improved performance, reduced fuel consumption, and enhanced safety features. By eliminating the mechanical components typically found in traditional engine control systems, FADEC minimizes points of failure, allowing for a more reliable operation of the engine. In contrast, options that suggest the presence of mechanical backups or increased pilot input do not accurately reflect the characteristics of FADEC systems, as they are designed to streamline engine management and automation. Similarly, limiting FADEC to basic engine management undermines its advanced capabilities that include full authority over multiple engine functions and parameters.