Which RMP is powered in an emergency electrical configuration?

In an emergency electrical configuration, RMP (Radio Management Panel) 1 is powered to ensure that critical communication and navigation capabilities remain available to the flight crew. This design choice allows pilots to continue operating essential systems, even if there is a loss of the primary electrical power supply. RMP 1 is prioritized for emergency power because it typically manages essential avionics and communication systems, which are vital for safety during critical phases of flight, such as approach and landing, especially in emergency situations.

RMPs 2, 3, and 4 provide additional functionality but are not designated as essential in the same way as RMP 1 for emergency operations. Therefore, in the event of a failure or a shift to emergency electrical configuration, the system ensures that RMP 1 remains operational to support continued flight operations and navigation safety.