Do you have any numbers on people who pass on the second time round? As it's an aptitude test I would have thought if you fail once, you probably fail again?
I believe that RN FATS are identical to RAF aircrew aptitude tests. While I don’t have exact statistics, scores tend to improve slightly each time you take them (like the RN, RAF applicants are not allowed to retake within 12 months).
Therefore, it depends what your scores were. If you were way under, you’re unlikely to improve sufficiently to pass no matter how many times you retake. If you only just failed however, you may be successful.
It’s then down to what the RN cut offs are. For instance, we get so many aircrew applicants in the RAF (over 20 OASC attendees for every one post) that we can afford to take only those applicants who demonstrate particularly strong aptitude (as well as the other qualities looked for during the full selection process). However, I’m not sure what the RN applicant-requirement ratio is.
Good luck!
Regards,
MM