Sorry, but I didn't see one consideration about this incident, and I'm curious about it:
Some posts mention the TCAS, and how it should have been followed or not, and if it should be followed at the first warning or not.
But hasn't at least one accident happened exactly because one aircraft followed the TCAS and the other didn't, in the Überlingen case [1] ?
I'm aware that only with the final report any conclusion can be draw, but anytime I see some incident where midair collision could have happened I remember that even TCAS isn't a miracle if not followed by both aircrafts.
[1]
https://en.wikipedia.org/wiki/%C3%9C...-air_collision