I was afraid of it but it was better than I thought
In fact I didn't prepare to COMPASS because I didn' knot how it looks like and what skills should I improve. COMPASS tests your orientation, memory, reflex, taskmenager, basic technical knowledge, your English (general and aviation), maths and physics (quite basic but you have to calculate quickly only with your head, pencil and piece of paper - no electronical devices). You will also have personal psychological test (over 200 questions how would you react in some kinds of situations) and quick, nice chat with examinators. On 2nd day is teamwork (how do you cooperate with other people) and chat again. As you can find on their website, the last step is a meeting with psychologist. Besides, all your papers must be OK - criminal record, medical certificate class 1, bank account statement, loan ability etc. And the most important - ENGLISH. All test, tasks and chats are in English. You might have best skills but it will be useless if you didn't understand an instruction of a task
Sorry for no details but I don't know how much I can tell and I don't want any troubles with Wizz
Have you already started your recruitment process?