There are all sorts of things you can do with a normal helicopter
 which are completely fatal.  For instance many helicopters can sever
 the tail boom with the main rotor under certain maneuvering
 situations.  The CH-46 suffers from a problem (as do all twin rotor
 designs) where the transmission can have a mechanical failure which
 causes the two rotor systems to get out of sync - causing loss of
 blades or at least loss of control.  There are lots of other problems
 with helicopters.  Engineers come up with ways to mitigate the
 issues..

Oh yeah..  Here's another neat one:

http://en.wikipedia.org/wiki/Ground_resonance



Matt-



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