For those asking about what kind of questions they're asking, I have a friend who recently completed all of the interviews and he said that on each stage of personal interviews he was asked very specific questions about light aircraft and (as was mentioned just above) reciprocating engines. Apparently it is very important to know about the first type of aircraft you will be flying in Adelaide. He also mentioned that as the interviews progressed (including stage 1 interview) they also asked very advanced questions about mach tuck and advantages of winglets. They also asked him to describe specific details on most of the current CX fleet of aircraft.
I hope this helps with your preparation. I'm still waiting on my call up.