When is the FADEC powered by the aircraft electrical system?

The FADEC (Full Authority Digital Engine Control) being powered by the aircraft electrical system below 50% N2 is critical for understanding engine control during different phases of operation. At low N2 speeds, specifically below 50%, the FADEC requires electrical power to ensure that it can manage the engine effectively.

During this phase, the engine might not be producing sufficient thrust, and the electrical system provides the necessary power to maintain optimal engine performance and control. This includes functions such as starting the engine, monitoring parameters, and executing specific control strategies that are essential for safe operation.

In contrast, above 50% N2, the engine is typically generating enough thrust, and often the FADEC can operate with other forms of power or backup systems. This characteristic is crucial for maintaining performance reliability and safety in various flight conditions.