Beyond monotonic trends in aircraft utilisation and productivity: The role of daily flight patterns

Productivity is one of the key factors that affect an aircraft’s economic value and environmental impact. It is defined as the number of available seat kilometres produced for a given period. It depends notably on the aircraft utilisation, defined as the time fraction during which an aircraft is airborne. This work combines data preprocessing, empirical methods and qualitative analysis to investigate it. Eurocontrol’s open flight dataset, partially incomplete and geographically limited, is corrected and filtered into a synthetically closed and operationally consistent one. It enables the observation of reliable short-term ground time patterns and complete daily aircraft flight sequences. Then, a flexible bin-based categorical measure of short-term utilisation dependence on previous and following flight block time is provided. It can be used to include aircraft productivity effects into a fleet assignment model. In contrast to standard models, it reveals that aircraft utilisation does not vary monotonically with block time: aircraft flights are grouped into integer and fractional daily flight sequences, resulting in specific ground time patterns. These findings allow to describe the relations between aircraft utilisation, aircraft design and airline operating strategies. The overall work contributes to a better understanding of the determinants of aircraft productivity and enriches fleet models aiming at predicting future fleets and their operating conditions, with emissions models as a corollary. It also provides valuable insights to optimise aircraft design.