MLB,
You appear to have had what we all assume is virtually impossible, which is two simultaneous engine failures without a common cause. All the examples mentioned above have had a common cause (fuel starvation, fuel icing, bird ingress etc.)
A friend (well known about these parts, though now no longer flying) had a double engine failure on a Baron. But that was caused by having chrome cylinders on one side and not the other and during rebuild the wrong rings were put on the wrong side - resulting in all 12 ring/cylinder interfaces being wrong and therefore both engines failing. That is explicable and understandable.
I am a cynical soul and consider the chances of the two failures being completely unconnected too low to consider seriously. I therefore want to hunt for the common cause. It does seem that both sides may be CSU related (overspeed (ie too fine) on one, underspeed (ie too coarse) on the other) so that sets me wondering whether you have had any work on the CSUs or props recently? Or indeed engine work?
The reason I ask is that many of us predicate our whole twin flying lives (I have been flying MEPs for 30 years) on the premise that unrelated failures don't happen. I fly to seriously remote places, where I would almost certainly die if the aircraft came down, and I only do it because I assume that one or other will keep working. I am also very conservative about fuel planning and IPA.
So I really want to know if this really was that seemingly impossible separate cause incident, or if you can think of anything.
Thank you,