This question already has an answer here:
About last Sunday night in the dark I was departing LAX on a redeye. We pulled away from the terminals (maybe 500m?), made a right. Looking back out the window I saw a BIG lighted X (maybe 20? 30? foot high - really bright!) flashing. I guess it was one of THESE but it had four rather than five per arm and REALLY bright. (I grabbed a completely hopeless video; I'll try to add it later.)
Now, just the previous day there was that incident at LAX where an airliner hit a supply truck, and toppled over the truck (some people in the truck were hurt even I believe).
Can the sign be used on situations other than runway closure? For example:
- almost certainly some drama, such as the mentioned truck-jumbo incident, or
- is it actually just a normal control sign that goes on an off? (Perhaps, to indicate "don't cross here, someone else is crossing" - or whatever.)
My impression was that it was at the "side" of a runway or taxiway, that is to say, as if crossing it. (Of course, my impression could be totally wrong.) Would these Xs be used in that way, or, only at one end of a runway?