the buck stops with the aircraft commanders maintaining a good look out
What is it with this desire to blame???
We are
human, the folk in those aircraft were
human. A human may do his utmost, highly-trained best, to achieve a good lookout,
but may still find himself in a collision. This is because the human eye and brain are very poor at identifying targets with which they will collide.
So please would you stop blaming the pilots and start simply accepting that the human is not good at lookout (in the same way he's not good at avoiding CFIT), and that technology may be the answer.
I pointed out, in the lost thread, that the leisure aviation community was unwilling to accept Mode S. I said that, in my view, those who voted against it gave up their right to bemoan collisions. If you can't be bothered to put up with the expense and weight of fitting a transponder, you have no right to worry about collision, because you could have done something to avoid it and you haven't.
Until and unless transponder carriage is mandatory, there will be no demonstrable case for fitting TCAS to small aircraft, and the opportunity to prevent collisions will continue to be missed.
Please remember too that the relatives and friends of those deceased will read this.
Once again, I offer my heartfelt condolences.