Air Transportation and Air Traffic Control
Fuel Burn Estimation
We assess fuel burn inefficiency by comparing estimated fuel burn for real world flights with the estimated optimal fuel burn. We use the Base of Aircraft Data (BADA) with corrections for environmental factors and public flight track data from FlightAware to estimate fuel burn. We decompose optimal 4-D trajectories into vertical and horizontal components and analyze the inefficiencies of each separately. We use Specific Ground Range to find optimal altitudes and speeds, and optimal control methods to find the optimal horizontal track. We consider actual flights through WATRS and CEP airspace regions during April 2016. Using the optimal altitude for actual flight Mach profiles, we compute mean inefficiencies of 4.75% in WATRS and 4.50% in CEP, both of which are 2 to 2.5 percentage points higher than studies using proprietary performance models and data. BADA overestimates optimal altitudes, leading to overestimates of inefficiency. Inefficiency due to off-optimal speed for WATRS is 2.18% vs. 1.86% in CEP. Using wind-optimal horizontal tracks gave mean inefficiencies 1.24% mean inefficiency in WATRS, and a 0.41% mean inefficiency in CEP. The results suggest that flights through WATRS and CEP have approximately the same inefficiency due to off-optimal altitudes. Flights through WATRS are further from their wind-optimal horizontal tracks than flights in CEP. Our results also show that reasonable estimates are possible using public data.