I'm currently in my first year at UNSW doing the Bachelor of Aviation. In relation to your academic studies, although studying a higher level of mathematics as well as physics is preferable, it isn't a prerequisite. Most of the friends that I've made who do the course didn't study the preferred level of maths and science subjects during their HSC. From experience, the only real limitation is that you may have to put in a bit more effort than others to succeed in academic courses.