What must be checked for flight after an aircraft has been refueled?

Choosing to ensure the correct fuel quantity and that no fuel leaks are present is critical after an aircraft has been refueled. This step is essential because fuel quantity directly affects the aircraft's performance and safety during flight. An insufficient fuel level could lead to an emergency situation in the air, while fuel leaks can create fire hazards or engine failure due to fuel contamination. Therefore, confirming that the fuel tanks contain the appropriate amount of fuel and that there are no signs of leaks ensures that the aircraft is safe to operate and ready for flight.

While verifying engine performance and temperature is important as well, it typically occurs during the pre-flight engine checks rather than specifically after refueling. Inspecting passenger safety equipment is also necessary for ensuring passenger safety, but it doesn't directly relate to the immediate concerns arising from the refueling process. Similarly, while checking the flight route for weather changes is a crucial part of flight planning, it is not specifically linked to the actions taken after refueling. Thus, the correct first step post-refueling is to verify fuel quantity and check for any leaks to maintain safety and operational readiness.