Mmmm. There have been some fast track commands based on previous experience and business need, but that's pushing it a bit given that there has to be the whole induction/initial training to do. As a principle, promotions should be based on seniority (assuming demonstrated suitability) but seats have to be filled. I make no predictions on time to command because growth is fast, people tend to take it as gospel and then get upset when it doesn't work out. A job applicant can have that discussion at interview.