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To determine whether the schedule is achievable with the truck fleet on site, use the Dispatch mode, and consider the Fleet Use Of Availability (UoAUA) which is reported for each truck in the Calendar. Although many sites have a historical UoAUA, this should not be an input (and is not when Dispatch mode is enabled). There is nothing wrong with varying the UoA UA for the truck fleet each day, provided the objectives of the schedule are met. The reported fleet use of availability gives an indication of how close to the edge the schedule is running. If the UoA UA is at 100% fleet use of availability, then if a truck goes down, the schedule may not be achievable (it still may be if there’s an opportunity to catch up later). If it’s at 50%, half the expected trucks could be inoperable, and the schedule is still achievable.
Note that if UoA UA for your site also includes times like when a truck driver does not show up for work, that should be instead be accounted for in either unplanned availability or one of the other availability fields. APS assumes that UoA UA is historically the percentage of time that the truck could be used, but intentionally wasn’t.
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