I have stated before in this thread: if you decide to go for the CTC scheme and do not get a job at the end, you will almost certainly not find a job in any other industry that pays you enough to allow you to pay off the loan.
To be brutally honest, I think that unless you are already a qualified doctor, lawyer, accountant or other similar professional BEFORE you embark on the course (and note I said "qualified" and not just a trainee/ graduate), you will NOT be able to pay the loan off at the conclusion of the course if you do not get placed. It is a fallacious argument to talk of having a good back-up plan. For example, I am a law graduate, but there is no way I can even contemplate a career as a barrister or a solicitor, as I can neither afford to take the BVC/ LPC, nor can I afford to spend another year in education without earning.