Please excuse the ramblings of an idiot above.
KTDA
Very interesting post, of which you make some valid points. However it is worth noting that above all else the profession you seek to join is a business and therefore its primary aim is to make money. That is why they can't invite all candidates to a two day + assessment. It would cost too much money!
To say that the door is automatically shut is not necessarily true either. Check out some of the CTC threads for proof that some people get invited back. A personality is defined by the age of 6 and character fairly set by the age of 25 years. The selection process is a snapshot, as indeed all aviation tests and check rides. They are judged largely by humans who make mistakes and therefore have an element of doubt. That’s simply aviation!
Computer testing is a very well defined art. If hypothetically one took the same test twice and got different results, I would guess the candidate had an off day. If one took two different tests, then expect two different results as they were most likely tailored to that company's needs and testing slightly different aspects of the candidates ability. Aptitude by definition can not be trained as such and no amount of private tuition will help.
If I were you, I would gather the experiences in and store them away for the next time. Secondly, don't give up. Get back in touch with these people and ask fro a second go. They may say no, but you lose nothing by asking. Lastly, as you are doing. Stay positive!
