What indicates an electrical fault in the system according to EICAS messages?

The presence of green needles on an EICAS (Engine Indication and Crew Alerting System) display signifies normal operating conditions for various engine parameters and does not indicate an electrical fault. In the context of EICAS messages, indicators reflect the status and health of aircraft systems.

Correctly identifying what does and does not represent a fault is crucial for pilots and crew members. An electrical fault would typically trigger a caution or warning indicated through other EICAS messages. The other choices either indicate specific operational statuses or parameters that aren't directly related to indicating an electrical fault. For example, "N1 FAN VIB" would alert the crew of abnormal vibrations from the fan, while "N1 REV and APR" highlights thrust reverser and takeoff/go-around modes, both of which are operational messages rather than fault indicators.

Therefore, understanding the specific meanings of EICAS messages, particularly the significance of green needles, aids pilots in monitoring their aircraft systems effectively and determining when they may need to investigate further for potential faults.