Originally Posted by
Lead Balloon
Then I think we've circled back to Capn Bloggs's point.
Perhaps try thinking about it like this:
The purpose of the dispatch calculation is to help determine the maximum weight for take-off, which must be the lesser of:
a. the take-off performance limited weight, and
b. the landing performance limited weight plus the weight of fuel/oil consumed in-flight.
The landing distance limited weight derived during that process is based on a bunch of regulatory factors and forecast conditions that are not particularly relevant for the actual landing. What's relevant are the actual conditions, weight, braking method, configuration, etc. The pilot uses that information to calculate the actual landing distance and factors it by 15% to determine the required landing distance. He or she can then compare the required distance with the distance available, to determine how much margin is available for the landing.
The following is an Airbus discussion of in-flight landing distance assessment:
https://safetyfirst.airbus.com/app/t...-distances.pdf