The changes between cycles are not significant with all the flight range CDFs having about the same shape and slope. The impact of cycle uncertainty is roughly the same order of magnitude as the impact of the cycle itself. If the variance were different from case to case, the slope of the CDFs would be visibly different between cases. Here the relative variance change over all cases is ~10%. In effect, this means that the control (cycle) parameters have a weak impact on design range variance.

The results for 3000 and 6000 n mi fuel burn mirror those of the aircraft design range. In this case too, component performance uncertainty is the same order of magnitude as the cycle itself. The fuel burn results show almost no difference between them, except the absolute amount of fuel consumed. Also, the variance of fuel burn is nearly constant for cycle uncertainties. Another interesting case is one in which the CDF is found on the far left of these plots. This is caused by the cycle analysis model change in the engine heat transfer design point midway through the CDF construction.

The CDFs for fan diameter and engine weight differ markedly from those for range and fuel burn. The variance due to component performance uncertainty is far less than the impact of changes in cycle parameters, as illustrated by the steep slope of the CDFs. This is expected since component performance usually does not have a first order effect on either engine weight or fan diameter. Engine weight and fan diameter are driven primarily by the cycle, and not by the noise parameters considered here.

From this small variance, engine weight and fan diameter need not be treated as probabilistic responses. With just component performance having only minor effects on weight and diameter, additional analysis resources are not needed to treat these probabilistically for the current problem formulation.