The only advice I can give you is just be yourself, it's a lot easier being oneself than someone you are not. What the interviewers will try to gauge is your personality and aptitude and how much of a fit you would be for the program. They look for certain personality traits and confidence, so go in with confidence.
They generally ask you to start off by telling them about yourself. They then feed off what info you give them and try to question you on those. So try to emphasize your strong points and whatever topic you have prepared so you can answer the questions they put to you better. I don't know why but asking about your weakness is a favorite question asked by HR. It's good to know about the company and the fleet. I don't know which branch of SIAEC you come from but if you have an engineering background, expect a few technical questions. Generally how turbine/piston engines work and how an airplane flies. Also they might ask you about your role in the company and go from there and be prepared to answer why you want to change your field and become a pilot. If they ask you a question you don't know, admit that you do not know it. They know you are not expected to know everything and know when you bs and will cross question and question you even deeper and before you know it you have dug yourself such a deep grave that it's the end of your interview.
You'll get different advice from different people because no two interviews are the same. Some interviews take 10 mins and some go 30 mins long. It all depends on how and what you say when they ask you to tell them about yourself and they proceed with the interview from there asking you questions on what you've told them.
If they skip the first interview for you since you already staff and go directly to the 2nd round, then search for SIA cadet pilot interview process and you should get links to the detailed process for the day, psychomotor tests and tea party info.
Hope this helps.
Good luck and let us know how it goes...
