What must a person do to initiate a line clear on a radar?

To initiate a line clear on a radar, the appropriate action is to press the Drop button. This action is essential because the Drop button is specifically designed to clear the line of sight on the radar display, allowing for a reset of the tracking function for new targets or to dismiss a target that’s no longer relevant. This step is crucial for maintaining effective radar operations, ensuring that the system accurately represents the current conditions without interference from previous data.

Other actions such as restarting the system, notifying a supervisor, or adjusting the settings may be relevant in different contexts or troubleshooting scenarios, but they do not directly initiate a line clear on the radar itself. Understanding the specific function of the Drop button is vital for effective radar operation and management.