Supporting controllers and flight crew is especially important in low‑visibility conditions. A line of red lights, known as stop bars, are already used to prevent aircraft entering a runway without air traffic control clearance. In addition to these physical safety nets, SESAR is advancing a novel virtual stop bar solution.
During low-visibility conditions, the ground controller can introduce procedural control to maintain safe separation, requiring clearance for aircraft to enter different areas. SESAR has developed solution #48 "Virtual block control in low-visibility procedures" to support the ground controller in providing surface movement guidance at these times, displaying red stop lights on the controller’s display. The virtual stop bars can be used by the controller to reduce block
sizes according to the conditions.
This SESAR solution #48 is now implemented in Riga and planned for Gdansk airports.
