To be so loud they were also deadly.
We had a mech walk into a running prop and another linemen did the same thing.
Like the commanders, its really tempting take that shortcut under the wing.
I know of 2 that crashed after a engine failure.
The engine out procedures are alot different than standard planes and jumping on the dead engines rudder will flip em on their backs.
I know as a former linemen that I HATED them as they required special fueling procedures.
I have seen many which were fueled incorrectly,one side all the way without balancing them out.
The mu2 will lean all the way over and I have seen one tip tank inches from the ground while the other was 8 feet up!
Also the tips tanks especially here in the hot south will build up presuure and if not vented prior to taking the cap off will get your attention.
I popped a cap standing on the ladder and BAM, had my sunglasses blown off and fell off the ladder:isadizzy:
Also the nose gear has a pin which needs to be taking out prior towing and hooked back up before flight.
I can also tell you what a smiley sounds and smells like when forgotten to be taken out before start

Overall the MU-2s were a major pain in the A** both for the pilot and linemen.
But did I say it was fast :d