Helicopter physics are unrealistic. Once the helicopter is at a hover, it acts as if it were resting on a pole. Specifically the AH/MH-9, if you were to apply lateral cyclic, the helicopter would pivot about a point about 2-3 feet below the skids, centered laterally on the aircraft.

Also, all helicopters descent rate's are incorrect. While at a hover, if you were to reduce the collective to the full down position, the helicopter would fall from the sky at a very high rate of vertical descent. In the game, they fall at about 1300-1500 feet per minute, which is about half of what a light helicopter would autorotate at with forward airspeed (2500-3000 fpm).