The FADEC is powered by ____ when the engine N2 is above 10%.

The FADEC is powered by ____ when the engine N2 is above 10%.

• A. the aircraft battery
• B. a magnetic alternator
• C. an external power source
• D. a dedicated FADEC power bus

Answer: (B)

The FADEC is designed to receive its normal, reliable power from the engine’s own electrical source once the engine is turning fast enough. When N2 is above about 10%, the engine-driven alternator (the magnetically generated power from the engine’s accessory gear train) provides the electrical supply to the FADEC. This arrangement gives the FADEC a stable power source that tracks engine speed and reduces dependence on the aircraft battery or ground power during climb and flight. Before reaching that speed (below roughly 10% N2), other sources such as the battery or external power are used to ensure the FADEC stays powered during start. The dedicated FADEC power bus is part of the electrical system, but the needed power for normal operation once the engine is running comes from the engine’s magnetic alternator.

The FADEC is designed to receive its normal, reliable power from the engine’s own electrical source once the engine is turning fast enough. When N2 is above about 10%, the engine-driven alternator (the magnetically generated power from the engine’s accessory gear train) provides the electrical supply to the FADEC. This arrangement gives the FADEC a stable power source that tracks engine speed and reduces dependence on the aircraft battery or ground power during climb and flight. Before reaching that speed (below roughly 10% N2), other sources such as the battery or external power are used to ensure the FADEC stays powered during start. The dedicated FADEC power bus is part of the electrical system, but the needed power for normal operation once the engine is running comes from the engine’s magnetic alternator.