FullWings,
I agree that GPWS alerts are most likely to happen during take-off and landing phases, and I obviously agree that airplanes congregate around airports. However, if there is rising terrain then either you are in "mountainous terrain" and the next legitimate airplane is 2,000 ft above, which at < 256 kts true leaves everyone lots of time, or you are near a protected approach channel (that you should be on) and there is no one close above. And you don't follow a GPWS pull-up for 30 seconds.
With TCAS, at more than 256 kts true, and airplanes legitimately 1,000 ft above (under RVSM, say), you have a required 30 second manoeuvre time, and you are in that other guy's legitimate airspace before your manoeuvre is over.
I can guarantee you that this situation has not been analysed thoroughly with regard to the interactions.
So I don't regard the situations as comparable.
Concerning the scenario I posed,
Originally Posted by FullWings
Follow the RA. The danger in aviation comes mostly from the aircraft you can't/haven't seen or aren't aware of. I would posit that you are unlikely to hit an aircraft that you have in plain sight
You seem to me to be giving conflicting answers here. "Follow the RA" says climb into the aircraft you are not painting. But you then say he's the danger. Exactly my view. The "aircraft in plain sight" that "you are unlikely to hit" is DHL. So that suggests you would manoeuvre contrary to what you suggested in the first sentence.
PBL