What does the display of 8s in all LCDs indicate during the TEST of the AAN LT switch?

When all LCDs display 8s during the TEST of the AAN LT (Aircraft Annunciator Lights) switch, it signifies that the functionality test is being executed correctly. This particular display is a built-in self-test feature indicative of the screens’ ability to perform and is meant to confirm that the display systems are operational. The sequence of 8s ensures that the crew can visually verify the integrity of the LCDs and that all pixels are functioning as expected.

The other options do not pertain to this specific functionality test. Engine malfunctions or configuration errors are not indicated through the display of 8s, and landing gear status is assessed through different indicators and signals, not through this self-test feature. Therefore, the appearance of 8s is directly tied to confirming that the display system is properly functioning through the test process.