CC, no disrespect intended, I just have a difference of opinion on some aspects. Doesn't neccessarily mean you're wrong, or I'm wrong, or either of us is wrong for that matter. Certainly appreciative of what you and others have to say about all this. That's why we're all here participating. I'm certainly not bashing the crew for anything they did or didn't do, so don't misunderstand me here.
If I was unfortunate enough to be caught out in cloud in a mountain valley and I had TAWS, and an appreciation of the best escape option came to this conclusion, I would go straight up the guts of the valley according to the TAWS display in a best angle of climb configuration. Aim being of course to keep as far away as possible from terrain that you could fly in to, then keep working at getting on an airway and following a procedure to get visual. This is hypothetical however, it hasn't happened to me, I don't know how it would work in practice. I'm just contemplating this question on reflection of the accident.
I just don't accept at this point that the TAWS will be all red and thus be of no real assistance, that's just not what I see on the TAWS display on the GNS530 when I'm flying in the PNG mountains, valleys included. You have a different opinion about this, fine. Sure, you get plenty of strange TAWS warnings, they can be annoying, but on the GNS530 the graphical display is good at giving you an appreciation of the surrounding terrain. Certainly a much better predictive appreciation of the terrain than not having it.
Your point about keeping a wing tip tight against the valley side is of course valid, to give you the best option of turning around, and the rest of it, but that only applies if you have and can maintain visual reference to the ground. We're talking here about, what do you do once having lost visual reference? That appears to be what happened here. The APNG flight could not land at Kokoda due to the weather (otherwise they would have landed), and they probably remained in the weather until the point of impact (otherwise they wouldn't have flown into the mountain).
As I said I don't know what the TAWS was indicating prior to the impact, there are too many unknown variables at play. For all I know it might not have given them any warning, and it might have been telling them they were somewhere other than where they were. What can't be argued is, if they had no visual reference, the only device they had for determining their position was the GPS. So obviously TAWS and the GPS will be an important aspect of the investigation, and if the data can be extracted from the unit then it could go along way towards explaining what happened.
And that's what people want to know, what happened.