I guess you are referring to the LINK-UP scheme(£10000). I'm not entirely sure how that is going to work. It seems a little desperate as you only get the money back in your last two years. I would have thought that most people in their last two years would probably hold out for the pension anyway, so what does it solve. If the scheme was open to people before their last two years, but you had to do the full service or pay the money back, that would make more sense AND act as a retention bonus.
That way the RAF would more or less guarantee the service of the pilots who otherwise would leave in their early 30's instead.