Originally Posted by bsieker
And yet, the Ueberlingen accident would not have happened, if neither aircraft had been equipped with TCAS.
Originally Posted by FullWings
Not possible I'm afraid. We all have to have it.
I understand that it is mandatory. Whether or not that is actually a
Good Thing is another matter.
Having two collision avoidance systems (radar/ATC/ground-based, and ground-independent aircraft-transponder-based) that may contradict each other is a real problem. Particularly and glaringly so if ATC instructs in one direction, and TCAS instructs in the opposite direction immediately afterwards. Do you reverse your manoeuvre to cross your conflict's original trajectory again?
ATC usually has a lot more information, than TCAS, and may instruct differently from TCAS to avoid further conflicts. The premise that ATC is already "out" when TCAS issues an RA does not hold.
Would you advocate doing away with the ground-based system and rely exclusively on TCAS? The trend towards
Free Flight will go in that direction, but we're not there yet.
Therefore we need a common standard in how we respond to it (which is where I came in on this discussion).
Common standards are a wonderful thing, if we can agree on what they should be for sound reasons. I don't see a silver-bullet solution that will cure all problems. It is clear that making following the RA compulsory in all cases is not it. (If it were, TCAS would be coupled to the autopilot to perform the avoidance manoeuvre automatically; I don't see anyone actively advocating that.)
Bernd