Advice from some of my friends who have done interviewing for CX. As long as you are not completely ignorant about aviation, spend 90% of your time on the HR questions. What would your boss say about you? Why do you want to leave etc.
How you answer these types of questions will make or break it...not knowing what frequency MLS transmits on is not important!
Dont be negative about anything. If you dont get a technical question right, how you handle not getting it right is far more important than the actual question.
Its kinda obvious really -and easy for me to say since i passed mine;-) WHo do you want to be sitting next to for hours at a time. Be that person.
cheers and good luck