the chopper seems to ignore gravity by clinging to steep slopes and staying there until it leaves the ground even when stationary or engines off.

instant stop, when touching down at high speed the chopper will stop instantly, it will not take any damage either.

sweeping noise at certain pitch, when flying forward when you reach a certain pitch, you will start to hear the slow sweeping sound the rotor blades make which you usually only hear when the rotors are turning slowly