If the primary flight display (PFD) and multifunction display (MFD) go blank, what could be an indication of the failure?

The presence of a single red X on the display serves as a critical indicator of a failure within the primary flight display (PFD) or multifunction display (MFD) systems. This red X is specifically designed to alert the pilot that some data is not available or that a particular system component has failed, indicating that the display has lost the ability to show certain information but may still display other critical data.

In aviation, the ability to quickly diagnose issues is essential for maintaining operational safety. The red X effectively signifies loss of redundancy or a failure of specific instruments, allowing pilots to assess their situation and take necessary actions, such as relying on backup systems or using alternate instruments if available.

Other indicators, such as complete loss of all instruments or display backlight failure, would not be represented by a single red X, but rather indicate different types of malfunctions or operational failures that might not specifically point to PFD or MFD issues. A blinking alarm, while a sign of caution, might not directly correspond to the loss of displays as clearly as the red X does. Thus, in the context of understanding display failures, the red X is the most relevant and informative response.