What does the RMU do if a malfunction is detected during the preflight test?

The RMU, or Radio Management Unit, plays a critical role in monitoring various systems within the aircraft. During the preflight test, if a malfunction is detected, the RMU is designed to enhance pilot awareness of potential issues by displaying a caution light. This immediate indication serves as a visual alert to the crew, allowing them to take appropriate action before flight.

The importance of this functionality lies in ensuring safety and operational readiness. By illuminating a caution light, the RMU not only informs the crew of the malfunction but also prompts them to investigate and troubleshoot the issue, thereby contributing to the overall safety of the flight.

While other options suggest different responses to a malfunction, displaying a caution light is the standard and operationally relevant way for the RMU to communicate issues. This helps maintain situational awareness and is aligned with cockpit resource management principles that prioritize clear and immediate communication of system status.