First 9 weeks at Halton will seem like a nice holiday when you get to Cranwell and the 10 week delights of A squadron. After you complete this phase, you will go to B squadron of 55. This part of training is the generic phase of aircrew training, after which you are streamed. Main point here is, you cannot apply for crewman as that decision is not yours, you may end up as a WSOp EW or ACO in the rear of a nimrod.(Of course your preferences are taken into account). PMA and your friendly instructors will have the final say in your future role though. Good luck with the application.