Calculation as a comparison in a precondition

Figure 133. A Calculation in a Preconditional Expression

In this figure, a numeric calculation is used as a comparison in the Filters section of the Rulesheet. The LHS of the expression essentially calculates the average pressure exerted by the total cargo load on the floor of the aircraft (sum of the cargo weights divided by the sum of the cargo containers' footprints). This result is compared to the RHS, which is simply the literal value 5. We might expect to see this type of calculation in a set of rules that deals with special cargos where a lot of weight is concentrated in a small area. This might, for example, require the use of special aircraft with sturdy, reinforced cargo bay floors. Such a Filter expression might be the first step in handling cargos that satisfy this special criterion.