Good advice and link provided above. Yes, if he is so freaked out by human contact at this point that he is attacking that relentlessly when you approach, your best bet is to slow things down a bit and try working with him while he's in the cage (with the door closed). Having a tussling match every time that he dives at you isn't going to do anything for either of you, and it certainly won't do anything to develop a bond.
Funny thing with birds is they often don't feel as though an idea is a good one unless it came from them. Domination is not the key to getting them to do as you ask. Rather, you have to get them to want what you want. Seems a fine distinction, but it makes all the difference in the world.
How to go about this? My suggestions are as follows:
1) if you currently free feed your 'too, try switching to 2 or 3 defined meals per day. Always provided in the cage. (Always in the cage so that it becomes associated with the satiation of hunger and not just as a place where he is locked up. You want it to be his home rather than his prison.) The reason why I say not to free feed is because it gives you a good training window between meals during which he will be more food motivated.
2) Convince him that you are not a threat. Sit as closely to his cage as you can without causing him any distress. Then just spend time with him talking in gentle, calming tones. You might have to stay at this stage for a few days. Possibly even weeks or more, depending on how stubborn he is and how thoroughly traumatized by his prior experiences. Point here, though, is to move closer and closer as his comfort level grows. Just never push farther than he is ready to accept. You can push boundaries from time to time, but never break them.
3) Build an association between you and tasty treats. First, find which treat is his favorite. Almonds or cashews are usually a good bet. As are sunflower seeds (Yes, sunflower seeds are unhealthy due to their fatty content, but they are fine when given as a treat rather than as a staple of his diet).
Once you've found his favorite treat(s), make sure that they are never a part of his regular meals. These special treats should be things he only gets in his special bonding time with you. You want him to see you and automatically think of those treats. Yes, bribery. Lol! Be patient and eventually he will muster the bravery to take the much anticipated treat from your hand. At that point, the sight of you will become a source of anticipation and pleasure rather than a source of fear and agitation. With time, you will see this change take hold.
3) Strategic timing. He should be hungry a half hour or so before say dinner, right? So that is the time that you start working on interactive training. At this point, unless he's made a 180 and has warmed to you completely, you're still working with him through the bars. But you can begin target training. Just do it by targeting him to different places in the cage with a pointer and rewarding him generously with treats and praise when he does it. Here is a great video on the basics of target training if you are unfamiliar: [ame="https://youtu.be/HaOicTtwIZo"]Beginners guide to target training parrots - YouTube[/ame]
4) Once he's working with you reliably and no longer wants to eat your face, you can open up the cage and attempt targeting him outside the cage. Again, baby steps. Don't push too far or too fast. As his comfort level continues to increase, you'll eventually be able to target him onto your hand.
