The personality questionnaire is just that...a questionnaire designed to see some of your personality. There are questions in there which seem to contradict themselves but I don't think that is the case. Some people do get disheartened when they don't pass it and you can understand why - there is nothing that can be 'changed or fixed' in order to pass it, nothing that can be learnt next time round. Your personality is your personality and the recruiters are looking for specific types of personality. There is no point in asking someone along to stage 2 who has a personality that doesn't suit the job, however ideal you feel the job may be for you...they are doing it for the greater good for both parties involved. How would you feel going through potentially a years worth of training, plus more after graduating from college only to find you hate the job? What if NATS brings in bonding and you have to pay them back for all the training that you've had and you can't afford to? You'd have to stay in a job you didn't like until the end of the contract, or you failed at a point in college then NATS lose out on hundreds of thousands of pounds that they've used to train a candidate...money which could have been better spent on someone suited to the role.
The personality test, while it can seem unfair when its not passed, is there for a very good reason. It eliminates the probability of the above happening (which could still happen at any point...however the recruitment process seems stringent enough to not allow many of these candidates through).
Doesn't stop it being gutting though does it...I know how I felt when I didn't pass stage 2 last year.
My advice for anyone who has the personality questionnaire coming up is to answer honestly and read the questions very carefully, then THINK about the answer and other answers you've selected. Don't rush it - don't worry if you've already been asked one question that is similar to another...just answer it once you've thought about it carefully. I scored each question from 1 to 4, 1 being most like me, 4 being least. Sometimes I could see clearly which order all 4 should go in, other times it was very difficult and that was when I thought about how I had answered previously and mainly used my scoring strategy. You can do no more.
Hope this helps.