Originally Posted by
Karel_x
What scenario prefers Occam's Razor in this case?
I really hate to say this but I honestly believe it is something along the lines: Sightseeing gone wrong.
Lost situational awareness and maybe thought they were in a different valley. One they saw before where you could fly through. Or thinking they were on the outside of the mountain range and flying alongside it (while the outer ridge being obscured).
This would explain why they did not initiate a climb once entering the canyon, without requiring total obscuration of both ridgelines while accidentally following exactly the direction of the canyon without seeing it.
Happy to stand corrected by the official report, though