Final answer:
The FAULT light in the RAT & EMER GEN light on an aircraft's EMER ELEC PWR PANEL indicates a fault in the emergency generator, which requires immediate attention as it is crucial for safety during power loss.
Step-by-step explanation:
The FAULT light in the RAT & EMER GEN light on an EMER ELEC PWR PANEL is an indication of a specific type of malfunction related to an aircraft's emergency power systems. The RAT in the acronym stands for Ram Air Turbine, which is a small turbine that deploys from the aircraft to provide emergency hydraulic and electrical power in the event of a loss of power. When the FAULT light illuminates, it indicates that there is a fault in the emergency generator, rather than any issues with the ratemeter, radio communication system, or emergency lighting system. The emergency generator is a critical component of an aircraft's safety systems, and a fault would mean that it might not function correctly in an emergency, jeopardizing aircraft safety and necessitating immediate attention from the flight crew or maintenance personnel.