The FADEC is powered by which source when N2 is above 10%?

The FADEC is powered by which source when N2 is above 10%?

• A. A Magnetic Alternator
• B. The main electrical bus
• C. The battery
• D. External power

Answer: (A)

When the engine starts and begins to spool up, the FADEC must have a reliable, immediate power source to control fuel, ignition, and timing. Once N2 passes about 10%, power for the FADEC is provided by the engine’s Magnetic Alternator, which is an engine-driven source that directly supplies the FADEC with the necessary 28 V DC. This arrangement ensures the FADEC stays powered as the engine comes up to speed, independent of the main electrical bus or ground power. The other sources have their roles in different situations: the main electrical bus and external power can supply FADEC power during normal operation or on the ground, and the battery can back up power in certain conditions, but the specific condition described—N2 above 10%—is designed around the engine-driven Magnetic Alternator powering the FADEC.

When the engine starts and begins to spool up, the FADEC must have a reliable, immediate power source to control fuel, ignition, and timing. Once N2 passes about 10%, power for the FADEC is provided by the engine’s Magnetic Alternator, which is an engine-driven source that directly supplies the FADEC with the necessary 28 V DC. This arrangement ensures the FADEC stays powered as the engine comes up to speed, independent of the main electrical bus or ground power.

The other sources have their roles in different situations: the main electrical bus and external power can supply FADEC power during normal operation or on the ground, and the battery can back up power in certain conditions, but the specific condition described—N2 above 10%—is designed around the engine-driven Magnetic Alternator powering the FADEC.