Done exercises against A10 and AH with pairs of fighters. AH with chain gun and Stinger, both operating in pairs. Fighters spent as much pulling high G to get out of the sight line of the wingman as they did trying to get into a firing position on the target. Also rarely managed it as the target was more manoeuvrable and close to the ground.
Best advise? If you get a cheap shot, gun/IR/radar against one that hasn´t seen you, it´s worth a shot. If he sees you and starting turning, leave it for another day. You´re going down to fight in his sandbox and there´s too much chance of being hit by something else less small arms or manpad to make it worthwhile.
Anyway, how can you tell zoomy hand combat stories about a fight with a chopper. No street cred whatsoever, particularly if you didn´t get a kill....