High wing loading is part of it. It's also largely because the things are so cheap for the capability. Not sure what the rules are in Yurop, but over here if the plane is under 12.5, a private pilot with a multi rating can get out of a seminole and fly off in an MU-2. Not the best idea.
Other factors: It uses spoilers for roll control rather than ailerons, which necessitates different engine out procedures. The gear is draggy during retraction, especially on the long bodies. The plane uses extremely effective full span flaps to make up for the high wing loading...an engine going out at low altitude and low speed with flaps 40, for example, means you'd better land straight ahead or you're rolling over and going in.
When the aircraft was put out of production, it was rapidly apprehended by low-cost cargo ops that it was a steal in terms of speed and price. At that point you have low time pilots in challenging conditions in a plane that flies a lot like a light jet who have probably upgraded from a Baron or similar and did all their training "in-house". If the guys doing the training know their stuff, that's not necessarily a bad thing, but if they don't...trouble.
All that said, the thing is built like a brick outhouse, flies like a dream (if a little heavy in the roll), can land on a dime, and is ridiculously efficient vs. the (slower) competition. Properly respected, it's not just a good airplane, it's an excellent one. MHO, etc. Again, having flown a comparable KA model, I'd much, much rather be in a Mitsi. The best advice I ever got from my crusty old highly experienced boss was "Don't go below 120 until you've got the field made and get to 120 just as fast as you possibly can on T/O". Follow that and it's a pussycat.
PS. If ag2a320 is still reading four years on, a lot of those tail numbers look real familiar. I flew the Mitsi for the successor to George's old outfit. I heard some extremely entertaining stories about George. Quite the character, by all accounts.
Last edited by TRF4EVR; 26th Feb 2010 at 07:10.