During a DCU warning while only one ED is operational, which page will the operable ED display?

• A. The operable ED remains on its current page.
• B. The operable ED will revert to the primary page and the warning message will be displayed.
• C. All warnings are suppressed automatically.
• D. The system powers down.

Answer: (B)

When only one display is working, a DCU warning prompts the remaining operable display to switch to the primary view and show the warning. This ensures the pilot immediately sees the most important flight information together with the alert about the degraded display. Keeping the current page could hide the warning or leave critical data on a non-primary screen, which is riskier in a degraded-display situation. Suppressing warnings or powering down would remove awareness or reduce safety, whereas reverting to the primary page with the warning guarantees visibility and clarity.