Open Time..A lottery
Open Time is a bit of a wishing well.There are a number of factors determining who gets what.
Low liners and those who are pay protected are first cab off the rank.Bidding up in hours helps.Bidding with no trade also helps.Overprojection of hours is also considered. Availability of reserve line holders is another factor.Seniority then kicks in.
Basically its a lottery with the O/T officer deciding who is the lucky winner