I posted this inside another thread in the general discussion forum, but I'm going to be getting more info over the next days and weeks so this would be a good time to start a thread on it!
Yesterday one of my room mates, who flies for another company, had the joy of a full fledged engine failure on a PT-6 on a 1900 (same type of plane I fly). Above 80 kts on the takeoff roll #1 engine lost power and (according to passengers) started shooting 5' or better flames out of the exhaust (lapping against the fuselage). Details on what exactly caused the failure will follow over the next weeks or months as they get a chance to examine it. Unfortunately for their MX, the aircraft is at an airport without a hanger they can use, so they will have to do an engine swap in the snow and associated cold. This is that company's only 1900, so it will be a week or two before they have it back operational. A comment was made that autofeather did not work in this case.
Fortunately for them, it didn't happen in any of the gravel strips they go into, which would have made for even more fun from the replacing the engine standpoint.
I was given an opportunity to look over the aircraft on the ground in Galena (where the failure happened) and made some observations.
1) The formerly clean fuselage has soot along the side (not unusual for a 1900, but I seemed to remember this one still beeing pretty clean before this).
2) The prop is locked up tight. This is a bad sign on a free turbine engine, where the prop should always turn freely. I suspect that this might be why autofeather didn't work. If the rest of the engine was still trying to spin and the prop was either jammed or encountering very heavy ressistance, there wouldn't be power from the prop but autofeather would still sense torque applied.
3) There are pieces of metal in the exhaust. Most, if not all, of the pieces look like they were either molten or very soft when they came out of the exhaust. Some of them are flat out puddled in droplets.
There are no signs externally of the failure, without getting a look in the exhaust or being able to try moving the prop (no holes in the cowlings etc).
And of course there was the obligatory passenger who wouldn't stop screaming.
