Pretty much as Thunderbug says except his timings are a little off. You become an SFO after 4 years, and then the next hoop to jump through is after 7 years. At each stage there is a management interview. If you do not have a FULL ATPL after seven years your seniority gets frozen - they cannot under UK law stop your progression up the salary scales - though they will still try this on. Hope this helps.