Level-offs in terminal areas and path stretches: Empirically estimating extra fuel burn rates in commercial aviation

Abstract

Improvements in air traffic management (ATM) and aircraft operations can have significant impacts on reducing jet fuel consumption. Although there are studies concerned with estimating this potential benefit, isolating the impacts of ATM inefficiencies on a certain air network is yet a complex task that relies on privately-owned data on aircraft performances and operational parameters, and assumptions regarding ideal and feasible flight paths, which may hamper proper monitoring by all stakeholders involved. To tackle those limitations, we propose a statistical approach based on public data of actual flights. Using econometric techniques, we estimated extra fuel burn rates due to path stretch and level segments inside origin and destination terminal areas. We applied the proposed methodology to the 20 most flown routes of the Brazilian domestic market in two different periods, covering 44 days in 2017 and 60 days in 2019. The results indicate that the model is capable of isolating the impacts of path stretch and level segments inside origin and destination terminal areas on the fuel consumption of the air network analyzed. Considering the 2019 sample as a reference, our estimates indicate that if all flights analyzed could fly great circle paths with continuous climbs and descents with the same operational parameters as those flights that could do so, the average potential savings would be between 189-231 L, mainly driven by horizontal inefficiency of descents. For vertical inefficiencies in terminal airspace, results indicate average potential savings per flight of about 4 L with continuous climbs and 20 L with continuous descents, if trajectories could reach the sample best performers, and considering the upper limit of the estimates. This study may help air navigation service providers, aviation authorities, airlines, and airports in monitoring ATM inefficiencies to prioritize operational improvement efforts, air traffic flow management (ATFM) measures, and technology investments.