Once you're on the property, you can bid any seat in any aircraft during an equipment bid. There is no requirement to move progressively from NB to WB, SO to FO to CPT. Most folks do by their own choice, but it's strickly based upon what you ask for and what your seniority will allow you to hold. For myself, I started as an SO in the 727 then bid ANC MD11 FO and got it 15 months later. Some new hires were lucky enough in recent bids to get the MD11 at ANC one or two months out of 727 SO school--I know several who were still on probation when they arrived at ANC, they were so new to the company! Again, what seat and aircraft you get once you're on the property is based soley upon your timing with an equipment bid, what you ask for, and what your seniority will hold, nothing else.