Hi Sinwing,
the vertical stabliziers on the BK117 have an soft area, a predertimined breaking area, which will break, if you mishandle the bird so far, that the blades will reach the stabilisers.
Had happend before - have seen the repair afterwards and you can tick the area with a coin, if you want to know, where it is.
If you handle the bird according to the handbook, it won´t happen...
Greetings Flying Bull