Maybe you can clear up something for me. I had heard that among the light twins, compared to the 310, only the Aerostar's fuel system was more demanding.
Regardless, could there have been a mechanical problem with the fuel system that took too much attention/time/altitude to solve and/or did the pilot mis-select pumps or tanks on the ground and then didn't catch his mistake?
Sometimes even a competent pilot gets distracted. I flew with a very competent pilot who, out of habit, grabbed the handle to raise the flaps during the roll out after landing in his brand new Aztec E.
Unfortunately, habit got that one wrong and it was the gear handle he grabbed, not the flaps. Oops...
You wouldn't be after you saw the maintenance bills.
There's a lot of things it could be. Initial speculation is always wrong.
PS: 310 fuel system isn't hard. Just remember the tip tanks are the mains and the fuel return system pumps fuel back to them, so you need to burn off fuel from those tanks before you try to use the aux (wing) tanks. I always ended up running the aux tanks dry by plan, usually ending up with an engine out for a moment followed by a nice yaw as I switched back to the mains...exciting for anyone with me...!