Runway incursion safeguards

This example represents a runway incursion as a barrier problem. The hazard is routine surface traffic near a runway; the top event is an unauthorised entry, not the collision that may follow. The left side identifies clearance and visibility threats and the barriers intended to stop them. The right side shows actions that can avoid or manage the outcome once the top event occurs. Use the diagram to structure a surface-safety conversation across pilots, controllers and vehicle operators. Airport procedures, equipment and roles vary, so replace the labels with the controls and terminology used locally. This qualitative diagram is not an operational clearance procedure or a replacement for aviation regulations.