What two criteria must be satisfied to fuel the aircraft while passengers are onboard?

The correct criteria for fueling the aircraft while passengers are onboard involve ensuring the minimum crew is present and that the MCD (Main Cabin Door) is open. Keeping the MCD open serves as a vital safety measure, allowing for immediate evacuation if necessary, and provides a clear path for emergency services to access the aircraft quickly if an unusual situation arises during fueling.

This procedure emphasizes the importance of safety and readiness in the event of an emergency and aligns with industry regulations and best practices that prioritize passenger welfare. Presence of the minimum crew ensures that there are trained personnel to manage the situation, monitor the fuel operation, and communicate effectively with the ground crew.