Twin Otter=Flying Slug
I am not quite sure I know what you are talking about.
I do know what I am talking about, and, having flown a Twin Otter for two or so years, I can testify that it is a most excellent utilitarian aircraft that does precisely what it was designed to do very well, without fuss or fanfare!
And has been doing so since 1965!
DeHavilland designed a winner!
Read all about it at https://en.wikipedia.org/wiki/De_Havilland_Canada_DHC-6_Twin_Otter.
The airframe of that flying slug is strong an robust. Unfortunately, it flies in some of the most trying conditions of terrain and weather. It will fly along most happily on one engine.
I have no idea what happened. The pilots will tell us. It is certified for flying in known icing conditions. I would suspect fuel starvation due to a massive error in fueling or fuel contamination leading to fuel starvation. Ice in fuel is bad, very bad.
A very odd crash happened at Heathrow Airport a few years ago. A 777 experienced fuel starvation over London due to extreme cold on a flight from Japan to Heathrow. Filters in the fuel system clogged due to wax that formed in the fuel due to the extreme cold temp of the fuel after an over the arctic flight. In effect the pilots had a glider over London with a couple of hundred people on board. The pilots were skilled and got the plane to Heathrow but landed short. They were out of altitude, speed, and power. Injuries were few and minor. Those pilots are to be commended.
The TwOtter is a fantastic, rugged aircraft for a variety of purposes. It’s perhaps the best bush plane ever. Still has its limitations, though.