Seeing it and being able to "touch it" are two different things. It's not easy to pick out a hovering helicopter that has you in his crosshairs from 3-5 miles away while positioned just above the treeline or with terrain and vegetation as a backdrop. Add in the fact that it can unmask just its radar wheel to acquire an enemy vehicle, identify it, categorize it, then either release a radar equipped hellfire at it autonomously, or pass the target off to another aircraft or weapons system within range . Besides, most attack helicopter operations are conducted under cover of darkness, making it near impossible to see an aircraft visually at those ranges and conditions.