Estimating stochastic air transport process times using the Fuzzy Critical Path Method: Determination of the Estimated aircraft Total Turnaround Time (ETTT)

Predicting both optimal and reliable aircraft turnaround time is one of the most critical tasks in ACDM flight scheduling plans. Considering the effects of randomness and fuzziness on the turnaround process duration, we transform the probability distribution of well-fitted sub-processes into a cumulated density function, equivalent to the fuzzy membership function (FMF), then identify the fuzzy membership grade of each turnaround sub-process by goodness-of-fit. Based on the Critical Path Method (CPM) technique and fuzzy set theory, the turnaround time, considering stochastic effects, is evaluated using the fuzzy critical path method (FCPM). To validate this calculation, we constructed the FMF from historical data and compared it with FCPM-based turnaround times. In addition, we utilize these historical data to generate fuzzy sets of different arrival delays using Frankfurt airport data of summer 2017 and conclude that delays are positively correlated with the FCPM-based turnaround process through a linear regression model.