[jcgoette]

WSJ article made it seem as if these lights were already in place:

"Airport officials also inspected lights meant to indicate when it isn’t safe for planes to venture across runways and verified they were working at that particular runway, according to the summary."

[dev_tty01]

So, the American flight didn't follow directions or the lights. If that turns out to be the case, wow.

[sandos]

Could also be that they were not correctly set, the pilots thinking "hey, no red lights, we can go! Its 100% safe".

[KyleBerezin]

This is a good example of how ADDITIONAL safety systems can sometime become the de-facto safety system. A similar problem can happen with firearms, where if a mechanical safety is on, people sometimes disregard other rules of safe firearm handling, leading to accidents.

Pilots have a lot of info coming in at any given time, and there has been a move to reduce the amount of info, so they can focus on the more important items. The answer isn't always more warning lights or alarms.

Edit: By "This is a good example..." I am referring to the hypothetical situation, I am not confirming this actually happened.

[addandsubtract]

Who are "they" in your sentence? I assume the lights and not the plane? Wouldn't lights like this be placed the same way on every airport implementing them?

[NoahKAndrews]

I think they meant that the lights may not have been set to the correct state.

[heavenlyblue]

I think what the parent want to say is that these lights do not exist. The sentence is written in a way that makes it seem they do (i.e. it's all theoretical in nature).