PBL,
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.
Hmmm. In the widebody I fly, a full-energy pull-up will generate sustained rates of climb of 5,000fpm+, when down to average landing weights. This is enough to cause an RA for someone 2,000' above you. Also, most airlines SOPs would require that a "hard" GPWS is followed by a max angle climb until out of immediate danger, then possibly further to MSA, especially in IMC. This is because if you trigger the GPWS you are probably not where you thought you were, so instead of finding out exactly where the ground is by using the aircraft structure as a probe, you get the hell out of there into a known environment. This may take some time, possibly a lot longer than 30 seconds.
One of my recent details involved flying north over Lake Geneva at 1,500' in landing config. until a full EGPWS was triggered. It took some time to get to 7,000' to clear the top of the mountain (as you keep the config. the same during the escape) but the angle of climb just overtook that of the slope.
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.
I think you've misunderstood my response. When I said "follow the RA" I wasn't thinking about whether it was climb, descend, monitor, increase, decrease, etc. I meant follow it whatever it says. I've done many sim exercises involving multiple aircraft encounters and it's interesting being non-handling and watching the whole thing unfold out of the window whilst monitoring what's on the cockpit displays. With "crossing climbs" and "squeezes" you get pretty close but there is always a "reality check" with relative bearings - if it's moving across the windscreen, you're not going to collide (unless it's filling it as well
). If for some reason the TCAS has failed to resolve the conflict then there is always the last-ditch option of a lateral or vertical change of course. This is likely to be an exceedingly rare event, so an early attempt to manoeuvre outside/against the TCAS guidance will diminish safety margins pretty much all of the time.
In your original scenario: "an advisory to manoeuvre to avoid a conflict from same-level or higher, and you have an aircraft below you in sight" there are at least three aircraft present. As far as I'm aware there were only two aircraft involved in the accident we're talking about?
joernstu,
If all manuals around the world contain the same instructions, all would be fine. But in the Ueberlingen accident, this was not the case
I'm sure they do now. I think, although I may be wrong, that the Tu154 Flight Manual for that airline was out of step with SOPs in pretty much every major carrier, even in 2002