READ. You don't get "zeroed out schedule". They only take the date over the dates(s) they need to "unstack" then revert to your preference.
Unstacking
Unstacking is a tool used during the PBS bid run process to reduce large stacks of open time on a certain day or a group of days.
Unstack Rules and Limitations
- In a non-holiday month, unstacking will be limited to 30% of line holders in each position in inverse seniority order.
- In a holiday month, unstacking will be limited to 50% of line holders in each position in inverse seniority order.
- “Holiday” means the following days: Memorial Day, July 4, Labor Day, Thanksgiving, Christmas, and New Year’s Day.
- If unstacking is utilized it will only be done to the lowest possible level in seniority to cover the open flying so as to affect the fewest number of pilots in each position.
- One unstack bid sheet is allowed. This is in addition to 3 regular bid sheets.
- The limit of 200 preferences includes the unstack bid sheet.
- Unstacking may span a day or several days.
- A pilot with vacation IS subject to unstacking
How It Works
Once it is determined that unstacking is necessary, the next step is to figure out how many trips need to be awarded during the unstacked period. Let’s say there are 20 pairings unassigned that all touch or start on Thanksgiving. Taking the number of reserves into account, it is determined that 10 of those 20 pairings need to get assigned during the bid run process. PrefBid will start with the most junior line holder and look for 10 pilots that are not already working on Thanksgiving, in inverse seniority order. Let’s say that PrefBid had to go 15 numbers up the seniority list to find 10 pilots not working on Thanksgiving. PrefBid will wipe all 15 affected schedules clean. It will then start building the most senior pilots’ schedule first. The first pairing that it awards is the pairing from the unstacked period, then the system will move back to bid sheet #1 (or whichever bid sheet you chose from the unstack bid sheet) and builds the rest of their schedule, according to the pilot’s preferences, around the unstacked pairing or pairings. PrefBid will continue building the rest of the schedules in seniority order.