Originally Posted by
Dynamiterabbit
To me, this is very simple and easy to understand. It can get complicated due to holiday coverage and complex requests, but the bottom line is that it’s just a line-by-line request, like computer coding, and it’s always possible to see where someone messed up if they didn’t get what they wanted.
Big picture, is this how United’s PBS works? Any key differences or headaches?
That's a reasonable way to think aobut it but it is not technically correct.
The system starts with everyone awarded a line that is built without regard for their bids. This is to establish the gline, line credit cap/average/floor, etc. It shows that a legal solution is possible with the current gline and system constraints.
Each pilot can have up to 20 bid groups. Each bid group is a separate bid. The solver will start with BG1. If BG1 has constraints that make a legal award impossible at his seniority then the BG will fail and the solver will move on to the next BG. If the pilot's last BG fails, the system moves on to complete mode where it systematically removes constraints from that final BG until a legal line can be awarded. This is useful because you can try to get something thta you may not be able to hold in your first BG then take a completely different approach in your subsequent bid groups.
A pilot at, or above, the gline is guaranteed a hard line as long as he does not big a reserve BG.
When the solver runs, it starts with those pre-bid lines and makes repeated passes through the list improving each line, based on the pilot's BGs. It keeps cycling through the list over and over until a point called cross-over is reached. Cross-over is a point where the bids are no longer being improved with each subsequent pass. This process runs for about two days for each bid status.
The BGs themselves are in two parts. The first part is to move the avaiable trips out of the supply pool into the seven weighted pools. A trip left in the supply pool in unavailalbe to the solver and can't be placed on your line (unless the BG ends up in completion mode). The second part modifies the constraints through a number of SET and WAIVE statements which either add contraints (SET) or loosens constraints (WAIVE). For exmaple, you can SET the work groups report or release time to the ranges you prefer or you can waive the minimum of 2 days off between work blocks, etc.
The user interface is not very intuitive but the concepts are not difficult. There is a project underway to revamp the user interface which will hopefully be a big improvement. It is worth your time to learn the system and how it works as you can produce good results at almost any seniority level if you do. Obviously, if you're very junior, you're going to get the trips that nobody wants and will work a lot of weekends but you'll still be able to build better lines than what you would have had left in a non-PBS system.