Gaz ED, from the point of view of the evading helicopter, it's difficult to see how a fast-mover is going to visually acquire, track and engage a slow, but moving target. One evasive manouevre is to run at max chat towards the attacking aircraft, staying low down so he has to continually lower his nose to keep sight of you. This would hopefully result in his CFIT behind you.
Slow jet (A10) or prop (Pucara) OTH........
Hunt and engage as pair, as was demonstrated against a couple of Scouts during Op Corporate.