Need 2 people. Place down a few AI and then fly a MH-9 around them while facing them (keep moving to make it a hard shot). Keep the helo at about 100-200m away and see how long it takes to get shot out. Do this a few times to see the variance for damage.
Then repeat the same with a friend flying the helo and you shooting at him. See how often you can shoot him out at range when he is moving fast and how often you end up shooting down the helo.