I don't get why this incident occurred, it should be quite preventable with the currently installed (quite simple) technology, namely status lights. https://en.

I don't get why this incident occurred, it should be quite preventable with the currently installed (quite simple) technology, namely status lights. https://en.wikipedia.org/wiki/Runway_status_lights https://en.wikipedia.org/wiki/Runway_status_lights They're apparently installed according to this PDF: https://www.faa.gov/air_traffic/technology/rwsl/media/JFK.pdf https://www.faa.gov/air_traffic/technology/rwsl/media/JFK.pd... In this case, planes coming from 04R (per the article) were crossing 04L. All the normal crossings of 04L I see in this PDF are equipped with the lights. So what went wrong?