This is the quickest and arguably the easiest mission to do on hard. A key thing to remember is that if you die while in the helicopter you will have to restart from the closest checkpoint, this is unlike the rest of the game where upon death you would respawn without penalty.
However it still a good idea to use the Hind as much as possible as it is very powerful, just stay away from the AA guns and move fast over the enemies to prevent being shot at. But the most important thing to do is keep an eye on the Helicopters health gauge, I would advise retreating to repair at about 40% and to repair before moving on to new areas just to be safe. So definatley keep your Power Tool on you and don't land near trees, it can be very dangerous. (Something I know all to well) you can use missiles to clear a small patch of trees if you want.