During an EICAS Control Panel power failure, which of the following buttons remains operational?

• A. PRI, STAT, CAS, STEP
• B. Only PRI and STAT
• C. All EICAS functions
• D. None operational

Answer: (A)

During a power fault on the EICAS Control Panel, only the functions that are tied to essential or standby power remain usable. The buttons PRI, STAT, CAS, and STEP stay operational because they access core, high-priority cockpit information that must be available even when full EICAS power is lost. PRI shows the primary engine and system data, STAT displays the current status and faults, CAS provides the crew alert summary, and STEP lets you cycle through messages or pages. Other EICAS functions rely on the main panel power and processing, so they don’t stay active. This combination lets the crew monitor the situation and navigate alerts even in a degraded electrical condition.