Originally Posted by joernstu
The notion of avoiding traffic by visual reference was introduced by you, as far as I am aware.
To be fair, it wasn't.
It was introduced by PBL, in post #20:
Originally Posted by PBL
[...]
They were faced with an "intruder" at 10 o'clock which they saw, and an unknown conflict at 2 o'clock which they didn't see, and for which they had an advisory to descend (that is, he was at or above their altitude).
[...] Or avoid him, descend towards an aircraft that you do see, and hope to avoid him using visual means?
(my emphasis)
However, this has nothing to do with "engineering facts", it is part of the argument why the Tupolev crew's actions were rational. A refutation has to offer more than "always follow the RA, because Eurocontrol says so in their marketing brochures, and I believe them, and it is also SOP."