Which system is typically checked remotely via the MCDU?

The correct answer relates to the ability of the Multi-Function Control Display Unit (MCDU) to interface with various aircraft systems for monitoring and diagnostics. The circuit breakers are designed to protect electrical systems from overloads, and their status can be checked via the MCDU. This remote check allows pilots to troubleshoot and diagnose problems without having to physically access the circuit breaker panels, improving efficiency and safety during flight operations.

In contrast, engine performance typically requires real-time telemetry and is monitored through specific engine indication systems rather than the MCDU. The passenger oxygen system is crucial for safety but usually does not lend itself to remote monitoring in the same manner as circuit breakers. The fuel management system is vital for operational efficiency and accuracy, yet monitoring it primarily relies on fuel gauges and dedicated displays for real-time management, rather than remote diagnostics via the MCDU. Thus, circuit breakers are the system that can be effectively checked remotely through the MCDU, allowing for proactive maintenance and awareness while the aircraft is in operation.