1. You need the MAV on your recon class.
2. Place MAV facing the tower where it will clear the platform when rising straight up.
3. Hit circle (PS3) or X (XBOX360) to exit out of the MAV.
4. Jump on top, make sure your are centered, and lay prone.
5. Go back into the MAV controller and DO NOT TOUCH THE LEFT JOYSTICK.
6. Rise straight up without stopping and starting too much or you will fall off.
7. Once above the platform move the left joystick forward slightly until on top of the platform and then exit out of the MAV.
8. You should now be on top.
You just put your MAV down, exit out of the controller, get on top (I like to lay down), then go back to controlling the MAV and elevate up without touching the left joystick. Once elevated SLOWLY move the MAV over what you want to land on and lower yourself down. It will take some practice and getting used to but once learned its pretty easy. Make sure that you put the MAV where you will clear the platform otherwise you will hit it, fall off, and die. :p