Which of the following is NOT one of the EICAS messages during a fire event?

In the context of EICAS (Engine Indication and Crew Alerting System) messages, it's important to recognize how fire events are communicated to the flight crew through specific alerts. The system is designed to give clear indications related to potential fire hazards within the aircraft.

The messages that do appear during a fire event include alerts for each engine, as well as smoke detection in key areas such as cargo compartments. The message ENG 1 FIRE serves to alert the crew of a fire condition in Engine 1, while CRG AFT SMOKE indicates smoke presence in the aft cargo area. Additionally, APU FIRE signals a critical fire situation pertaining to the Auxiliary Power Unit.

The absence of the ENG 3 FIRE message highlights the aircraft's configuration; the Embraer Regional Jet does not possess a third engine, making this particular alert non-existent. Understanding this system's operation and the specific EICAS messages helps maintain situational awareness and readiness in case of an emergency, especially related to fire events on board.