During the grounding procedure, what is connected first?

The grounding procedure is a critical safety measure in aviation to prevent static electricity buildup and ensure safety during maintenance or fueling operations. The correct action is to connect the ground first before attaching any equipment to the aircraft. This approach helps to safely discharge any static electricity that may be present in the aircraft before any connections are made that could create sparks or other hazards.

By connecting the ground first, you establish a safe path for electrical discharge. Once the ground is secured to the aircraft, it becomes less likely that any static charge could cause ignition when connecting additional equipment. This is especially important during operations such as refueling, where there is a heightened risk of fire due to flammable fuel vapors.

In contrast to the other options, connecting the aircraft to a charging station or connecting the aircraft directly to the ground without a proper grounding first could lead to dangerous situations if a discharge occurs. Thus, the safest and most prudent practice is to ensure the grounding is established first.