What is the first action to take when using a static discharge kit?

When using a static discharge kit, the first action to take is to ground the aircraft with the grounding cable. Grounding the aircraft is crucial because it helps to prevent the buildup of static electricity, which can pose risk during fuel transfer operations or when working with sensitive electrical systems. By establishing a proper ground connection, any static charge that may have accumulated on the aircraft is safely dissipated into the ground, reducing the likelihood of spark or electrical discharge that could lead to accidents or equipment damage.

Each of the other options represents important procedural actions, but grounding the aircraft is foundational and must be the first step to ensure a safe working environment. Checking aircraft systems, inspecting the discharge kit, and signaling team members can only be safely executed once the risk from static discharge has been mitigated through grounding.