What action should you take if the automatic transfer fails with a loss of all generators?

What action should you take if the automatic transfer fails with a loss of all generators?

• A. Reset the transfer switch
• B. Attempt a manual transfer
• C. Verify external power
• D. Press the Essential Power Button

Answer: (D)

If all generators are lost and the automatic transfer cannot restore power, the essential step is to push the Essential Power Button. This action engages the essential power path, connecting the essential electrical bus to its backup power source (typically the battery/essential power source), so critical systems stay powered even when the generator-based power is unavailable. It bypasses the failed transfer logic and ensures that avionics, flight controls, and other essential equipment continue to have power. Other actions like resetting the transfer switch or attempting a manual transfer won’t reliably restore power to the essential bus when there’s no generator supply, and verifying external power isn’t applicable if none is available. The Essential Power Button is specifically designed for this exact situation to maintain essential systems when automatic transfer cannot be relied upon.

If all generators are lost and the automatic transfer cannot restore power, the essential step is to push the Essential Power Button. This action engages the essential power path, connecting the essential electrical bus to its backup power source (typically the battery/essential power source), so critical systems stay powered even when the generator-based power is unavailable. It bypasses the failed transfer logic and ensures that avionics, flight controls, and other essential equipment continue to have power.

Other actions like resetting the transfer switch or attempting a manual transfer won’t reliably restore power to the essential bus when there’s no generator supply, and verifying external power isn’t applicable if none is available. The Essential Power Button is specifically designed for this exact situation to maintain essential systems when automatic transfer cannot be relied upon.