as long as you can sit in the office for a few weeks, and can crawl your way to the BOS desk, then you have a chance.
The managers in there do have some input, but the main thing is you have to be known by the ST and AW. ( by the way the managers should have some say lets be realistic here!)
The process however is no where near as corrupt as when the Tamil tiger was in charge, nepotism at its highest, the corruption and the "most favored" treatment was used then for the CSM intake.
Promotion in any industry has its flaws, I personally think they should take a persons record and their BPR as a key indicator!
The applicant should serve at least 2 years as a CSS and even that is a short time, however its unwise to take them straight from the F/A ranks.