Originally Posted by
rp2pilot
You can please some of the people all of the time, and all of the people some of the time. The old system (line bidding) had issues too. If the none of the prebuilt lines had what you wanted, you were pretty much out of luck regardless of your seniority. At least with PBS, you can often get some of the things you're looking for (specific dates off, layover cities, departure times, etc.). Honestly, commuters (I don't commute) are probably far better off with PBS than they were with the old system. jmho
From the Prefbid site, written almost 10 years ago by an L-CAL PBS instructor:
Overall Solution Constraints essentially means that you aren't senior enough for it to build the line you wanted, even though there may have been trips available that would have worked.
I'll explain how that works under PBS and then compare it to the way lines were constructed under the old system.
Under PBS, the company uses a formula to set the G-Line, above which every bidder who wants one is guaranteed a line. In order to meet that requirement, PBS looks ahead after constructing lines for each bidder to be sure there are enough trips left to complete the overall solution for the entire BES. At some point down the seniority list, bidders ask for lines that, if awarded, would not allow PBS to complete the overall solution. That seems to be what happened in your case. If PBS awarded you a line based on this bid group, it could not complete the solution for the entire BES.
Now, this isn't really much different from what we saw with preconstructed lines except that the process is visible instead of behind the scenes. When our line construction guys build lines, they can only build so many high time max day off lines before they have to start building 'less desirable' lines. There may be pairings available for them to build better lines, but if they did, there wouldn't be enough pairings to build the required number of lines to complete the solution.
One way to check this is to look at the preconstructed lines. You could cherry pick trips from several 'less desireble' lines to build a higher time line with more days off. But that line wasn't constructed because it wouldn't allow the solution to be completed.
PBS places an emphasis on seniority by allowing senior bidders to do the cherry picking until it reaches that point where solution constraints kick in. When you find that a bid group failed due to solution constraints, that's essentially the same as saying that your not senior enough to hold what you wanted. Just like what we had with preconstructed lines, only a certain number of bidders were able to hold the 'desirable' lines while less senior bidders would get lines that may not be as desirable.
Hope that makes sense. The fact that we can see the solution constraints now where we couldn't before has caused some frustrations, but the transparancy is the only real difference. The constraints were always there but handled behind the scenes.