Originally Posted by joernstu
I can't remember advising anyone not to follow a RA, but surely you will prove me wrong?
Originally Posted by punkalouver
bsieker(one of your like minded coworkers) in effect said so in my opinion in post #101 when he said the Tupolev crew's decision was rational
I would have let it rest, but since you seem to have misread my post, I will explain it again.
Describing a course of action as a
rational choice does not mean that it is the only choice, nor necessarily the only rational choice, nor necessarily the best choice, nor even that the actor(s) involved acted rationally when choosing that option.
The scenario which I described in more detail, in which following ATC was the
only rational choice, is the scenario in which that crew did not receive an RA at all, because of inop TCAS.
The point being that all parties following their respective rational (in this case, even
best) choices, one of which is following the RA, the other, in the absence of an RA, following ATC, (courses of action, I take it, you would approve) and yet they end up in a collision.
The problem is not so much following an RA, but the poorly-understood and unregulated (non-)interaction between TCAS and ATC.
This, as we have seen, may lead to collisions, although and because one crew follows its RA.
You say that you
always follow the RA because the risk is lower than following ATC, where both are in conflict, but without giving even the hint of an argument for it, in the face of strong arguments (i. e. Ueberlingen) to the contrary. The Boeing pilot could not know if the Tupolev's TCAS was inop, or if they were just ignoring its RA.
If you misconstrue this as me generally recommending not following RAs, I cannot help it.
I am merely pointing to what I think is a big problem with collision avoidance in the larger system "air traffic", not looking at TCAS as an isolated system, but at the larger socio-technical system, comprising (at least) of two or more TCAS systems, two or more flight crews, several air traffic controllers, primary and secondary radar systems, ATC software, ...
Bernd