What is necessary before boarding if there are only 3 CC on board?

In scenarios where there are only three cabin crew members (CC) on board, ensuring that fueling is completed is vital for safety and compliance with operational procedures. Adequate staffing is crucial for managing boarding processes, safety checks, and emergency situations. Therefore, if the number of cabin crew is below the required standard based on the aircraft’s capacity or regulations, it is essential that fueling takes place only when there are enough crew members, possibly signaling that additional crew members (like another CC) need to be on board to meet safety standards before proceeding with any further operations, including boarding.

While other options may seem relevant, they do not address the immediate safety concern regarding the minimum number of required cabin crew operationally needed before fueling or boarding can take place. Ensuring the proper staffing and readiness of the cabin crew is a foundational aspect of safe flight operations.