If lightning is within a specific distance of the flight-line, what action must be taken?

When lightning is within a specific distance of the flight-line, safety is the top priority. Ceasing operations and seeking shelter is essential to protect personnel from the dangers associated with lightning strikes. Lightning poses a significant risk, especially in an environment where fuel and aircraft are present, as it can cause fires and injuries. By ensuring that all personnel are safely sheltered, the operation can prevent potential hazards and maintain a safe working environment until the threat passes.

Other options may suggest continuing with operations, notifying command, or preparing for takeoff, but these do not adequately prioritize safety in the presence of lightning, which can strike unexpectedly and with great force.