What should be done if the vent box overfill light comes on during refueling?

When the vent box overfill light activates during refueling, immediate action is required to ensure safety and prevent potential hazards, such as fuel spills or tank damage. Shutting down the refueling operation right away helps to mitigate the risk of overfilling, which can lead to serious situations including environmental contamination and safety risks for personnel and equipment.

This precautionary measure is essential because the overfill light indicates that fuel is nearing or has exceeded safe levels in the vent box, suggesting a malfunction or issue in the refueling system. By stopping the operation at this point, the pilot can prevent further complications, allowing for a proper assessment of the situation before proceeding.

In contrast to continuing normal operations or checking the fill valve status, which might ignore the critical warning, immediate cessation of refueling operations allows for a thorough investigation and appropriate corrective actions to be taken. Therefore, shutting down the operation is the most responsible and safe response to the vent box overfill warning.