What EICAS message is displayed if the APU catches fire while on the ground?

When the APU (Auxiliary Power Unit) catches fire while on the ground, the EICAS (Engine Indication and Crew Alerting System) will display the message "APU FIRE." This message serves as an immediate and critical alert to the flight crew, indicating that there is an active fire hazard related to the APU. The explicitness of the "APU FIRE" message allows the crew to take necessary emergency measures, such as activating fire suppression systems and preparing for potential evacuation procedures.

The other messages reflect different conditions related to the APU but do not convey the same urgency or specific situation as the "APU FIRE" alert. For instance, "APU FAULT" typically indicates a system malfunction that does not necessarily involve a fire, while "APU SHUTDOWN" indicates that the APU has been turned off under normal operations, and "APU OVERHEAT" suggests a high-temperature condition that does not confirm the presence of an actual fire. Thus, in the context of an active fire scenario, the clarity and direct warning provided by the "APU FIRE" message is paramount for safety and appropriate response.