What does the FOM require regarding the use of first officer's systems?

The requirement that both pilots must be familiarized and ready to take over as needed aligns with the principles of crew resource management and safety in aviation. It ensures that both the captain and first officer have a comprehensive understanding of the aircraft systems so that they can effectively collaborate and respond to various in-flight situations.

This balanced approach to system knowledge promotes situational awareness and allows either pilot to take control if necessary, contributing to overall flight safety and operational efficiency. By being equally familiar with the systems, both pilots can effectively manage any malfunctions or emergencies, which is a critical aspect of their roles.

The other options suggest limitations or hierarchies that could compromise safety. For instance, suggesting that only the captain should familiarize with the systems undermines the importance of teamwork in the cockpit. Similarly, the idea that familiarization should only occur once per training cycle does not account for the dynamic nature of aviation, where ongoing knowledge and currency are essential. Lastly, stating that first officers should always defer to the captain's decisions may overlook the importance of assertiveness and communication, especially in safety-critical scenarios.