Cheers for the info MJ. I'm a TP man, but only have extensive experience handling 4's (Hercs) - we would regularly practice 2 engine overshoots in the ac and MOS EFATOS in the sim (climbout below Vmca1) so I'm generally aware of how tricky it can get... and how quickly. Still though, something doesn't add up with those speed / alt plots.
Forgive the ignorance of more modern types... but when you say 'secured', do you mean feathered AND braked, or just feathered? From the vids & subsequent recovery pics, the left prop seems feathered, but still turning.
I think we may be missing a vital piece of info somewhere?