What action is taken when connecting the pre-oiler to the engine/AMAD?

When connecting the pre-oiler to the engine/AMAD, ensuring proper grounding is critical. Grounding is necessary to prevent static electricity build-up that can occur during the fueling process. This static could create a hazardous situation, potentially leading to a fire or explosion, especially in an aircraft environment where flammable materials are present. Proper grounding ensures that any electrical charges are safely dissipated.

Connecting the pre-oiler without taking grounding precautions poses risks, which is why this step is fundamental in the procedure. This action is paired with other necessary safety measures in aviation maintenance to uphold safety standards and protect personnel and equipment.