Vector801,
I hate to be the bearer of bad news but I would suggest it is very unlikely that you will be given the opportunity to have a third go at FAT's. It is unusual to be given a second chance. When I was an ACLO, I enquired about getting some of my candidates at the time a second chance a FAT's, CDR AIR at AIB said no and suggested that they go for Warfare. The problem with FAT's is that once you have done them once or even twice you know what they are all about and are therefore they are not achieving their aim. People are also very unlikley to improve on their scores if they go again. You either have it or you don't. You also need to have a time period of 12 months between doing both FAT's and AIB again(6 months in exceptional circumstances in the case of AIB). If you have failed AIB you only have one more shot at it. If you pass and don't get in for the entry you want, the pass lasts 12 months and you are automatically put on the list for all the subsequent entries during that period.
In terms of crossing over from rotary wing to fixed wing in the RN, it is called the AIR 309 Course. You need to be pretty good at flying helicopters and have passed your Certificate of Competence (CofC), had a good trap ride and be recommended by your squadron. They also look back at your EFT reports and you need to have averaged 3.8 or more to be in with a chance, less than 3.5 and you can forget it. They look at this because they reckon these scores have a good correlation with the numbers that get through Valley and onto Harrier OCU.
However don't let any of what I have said put you off. If you are really serious about being Aircrew in the RN, I would stick another application in and keep at it. Times change and policies change. The above was the policy when I was an ACLO which is a while ago now. The RN is going on a major recruitment drive for aircrew at the moment and they will pretty much take anybody who passes all three FATs and AIB, which was not the case 12 months ago. However this has a few ramifications later in the training pipeline and I would not be surprised if the chop rate increases again, as standards in flying training have not dropped. It requires a lot of determination and hard work to become a Naval Aviator, but if you are serious about a career in the RN get your head down, grit your teeth and crack on, it will be well worth it in the end.
I wouldn't do anything else!
FLY NAVY!
Jucky