Protocol for Operators Viewing Illuminated RWSL
Pilot and vehicle operator compliance with established protocol for viewing illuminated red status lights is imperative for the system to be effective. Users of the system are trained to respond to Runway Status Lights in the following ways:
Runway Entrance Lights (RELs)
- When RELs illuminate red, the runway is unsafe to enter or cross and pilots should stop immediately
- When the lights are off, pilots/vehicle operators may not enter or cross the runway without ATC clearance
Takeoff Hold Lights (THLs)
- If in position and hold on the runway and THLs illuminate red, the runway is not safe for takeoff and pilots should remain in position for takeoff
- If takeoff roll has begun and illuminated THLs are observed, pilots should safely stop the aircraft and notify ATC that they are stopped because of red lights
Runway Intersection Lights (RILs)
- When RILs illuminate red, the runway/runway intersection ahead is unsafe for entry or crossing and pilots and vehicle operators should safely stop before the intersecting runway
In all cases, if following the established protocol is not safe, pilots should proceed according to their best judgment of safety (understanding that illuminated RWSL indicates a potential conflict exists) and contact ATC at the earliest opportunity.
When RWSL lights contradict air traffic clearances, pilots and vehicle operators are trained to respond first to the status lights since they are intended to serve as a backup safety net when the humans in the loop make errors. Conversely, pilots and vehicle operators are trained that RWSL is an advisory safety system only and that RWSL off NEVER should be perceived as an air traffic control clearance. RWSL only has two states, 1) On – lights illuminate red and 2) Off – lights do not illuminate. RWSL never illuminates green lights to convey safety or clearance.