What is the engine ignition powered by?

• A. System A from DC Essential Bus and System B from the Battery Bus through a static inverter
• B. System A from AC Essential Bus and System B from the DC Bus through an inverter
• C. System A from AC Essential Bus and System B from the Battery Bus directly
• D. System A from the Battery Bus and System B from the AC Essential Bus

Answer: (A)

Engine ignition is designed as a dual-channel system with independent power sources to keep the spark alive even if one source fails. In this arrangement one ignition channel (System A) is fed directly from the DC Essential Bus, providing a solid, critical DC supply. The other channel (System B) gets power from the Battery Bus and uses a static inverter to generate the AC power needed by the ignition coils. The inverter is essential because the ignition system requires AC energy for the spark plugs, and the Battery Bus alone supplies DC, so the inverter converts that DC into the appropriate AC. This setup ensures redundancy and reliability even if one bus is unavailable.

The other possibilities don’t fit because they either rely on the AC Essential Bus for both channels (reducing redundancy), place the inverter in the wrong path, or provide direct DC powering where AC is required for ignition, which would not meet the ignition system’s power needs.