I had my aircrew selection back in August of 2016, and I remember scouring this forum for any extra information that I could to help me 'get an edge' or what I should be studying before arriving in Trenton. While I'm not going to give away any answers or specific details on the test, I'll just post a few things that I found helpful.
http://rcaf-arc.forces.gc.ca/en/cf-aircrew-selection-centre/candidate-guide.page
This is the candidate guide for the selection centre. Read it. Read it again! Click on the images under Aptitude Tests and read the image descriptions. No one is trying to trick you when you go for aircrew selection, but make sure you read and comprehend all instruction given to you. Most of the tests will give you a small practice window before starting the real test so you can get a feel of the keys/controls needed. If you're female, I would recommend wearing flats or dress shoes since there are foot pedals used occasionally. Bring some spare change if you would like a coffee. The centre does have a coffee maker, and make sure you wash your mug when finished.
Check and double check that you have all required paperwork before heading to Trenton. Maybe consider bringing a spare envelope to hold your receipts so they don't get misplaced.
http://www.speeddistancetime.info This is a handy site to brush up on your mental math. I also subscribed to Lumosity and practiced daily before aircrew selection. I felt it helped me be more mentally flexible, but of course your mileage may vary.
During testing, you won't have any idea of how you're doing until it's over. 'I'm either doing alright, or failing miserably' was common to hear during breaks. Try as hard as you can even if you think you may be doing poorly. You may be doing better than you thought. Don't give up. Remember to breathe and enjoy your time in Trenton! Some of the aptitude tests could be considered fun.
In my search for any extra information, I ran across an e-book called '
RAF Officer Aircrew Selection Centre OASC: How to become an RAF Officer (The Testing Series)'. Don't bother with it. While the Canadian Forces did buy the testing system that the Royal Air Force uses to screen candidates, it didn't offer me any extra advice that I couldn't find elsewhere. The RAF also has a 'practical' section of testing that Canada did not implement. If you want to throw $10 in a hole like I did, there's better places to waste your money.