Which panels can be used to regain ECP operation after it is inhibited due to ED failures?

• A. The MFD reversionary panel only.
• B. The Source Selector Panel only.
• C. Power cycle the DCU.
• D. MFD reversionary panel or the source selector panel.

Answer: (D)

Redundancy and recovery paths for ECP when display faults (ED failures) inhibit operation. When the ED system blocks normal ECP operation, there are built-in back-up routes to restore control and display functionality without waiting for a full system reset.

Using the MFD reversionary panel provides a separate display/control path that can take over if the primary MFD path is unavailable. This back-up route lets you regain ECP operation by routing essential signals through a functioning display/control channel.

The Source Selector Panel offers another way to re-establish ECP operation by selecting an alternative display source or path that is still healthy, effectively re-enabling the ECP without needing a full reset.

Power cycling the DCU is not the preferred recovery method for ED-induced inhibition because it may not address the specific fault and can take longer, with no guaranteed restoration of ECP.

So, the best approach is to use either the MFD reversionary panel or the source selector panel to regain ECP operation after ED failures.