When will both channels of the FADEC become active?

When will both channels of the FADEC become active?

• A. engine overspeed
• B. engine start
• C. idle
• D. shutdown

Answer: (A)

FADEC redundancy is built so there are two channels that monitor the same engine data. In normal operation one channel acts as the primary controller while the other stays in hot standby, always powered and watching for faults. When an overspeed condition occurs, protective logic activates both channels so they can jointly validate the fault and drive a safe response, such as reducing fuel or shutting the engine if needed. This dual involvement ensures that no single channel fault can prevent a protective action. Start, idle, and shutdown are normal operating states where only the primary channel controls, with the other simply monitoring or taking over if the primary fails.

FADEC redundancy is built so there are two channels that monitor the same engine data. In normal operation one channel acts as the primary controller while the other stays in hot standby, always powered and watching for faults. When an overspeed condition occurs, protective logic activates both channels so they can jointly validate the fault and drive a safe response, such as reducing fuel or shutting the engine if needed. This dual involvement ensures that no single channel fault can prevent a protective action. Start, idle, and shutdown are normal operating states where only the primary channel controls, with the other simply monitoring or taking over if the primary fails.