Scenario 1:
I changed the controll for increasing height and lowering to Z and X. And pedal left and right to Q and E.
I unbound the other helicopter keys that would been affected by this change.

The result was when I was using E the helicopter turned its nose left and down, instead of just left(which worked fine if I used END which is one of the default keys).

Scenario 2:
This time I let the keys stay default, changed the key settings to ARMA 2 and changed the pitch nose up to mouse up(instead of mouse down) and pitch nose down to mouse down(instead of mouse up).

This resulted in a some sort of counter effect, so when I tried pitching the nose up or down nothing happened. As if both nose up and down was bound to both up and down movement of the mouse.