Fuel Efficient Air Traffic Control Maryam Kamgarpour, PhD Student Claire Tomlin, Research Adviser John Robinson, NASA Ames Research Center December 17, 2009

Outline Motivations for Improving Fuel Efficiency of Air Transportation Background on Air Traffic Control Study on Fuel Efficient Approach Procedure Conclusions and Future Work

Motivations Air transportation is responsible for about 25% of global warming contributions of the transportation sector in the United States [International Council for Clean Transportation, 2009] Air Traffic causes 4% of Radiative Forcing – This number has grown 45% since 1992 – It is predicted to grow by 150% in 2036

Improving Environmental Performance of Air Transportation Use of bio fuels – Currently algae-based fuels being tested – Challenges such as energy efficiency Design of fuel efficient aircraft – Improving engine and aerodynamics design – Use of light weight composite material Design of fuel optimal routes

Improvement in Aircraft Design Source: The International Council of Clean Transportation 2009

Design of Fuel Efficient Routes For each aircraft one can optimize: – Cruise altitude and speed – Routes based on wind and weather – Climb and descent profiles However, aircraft must operate within the constraints of the air traffic structure

Air Traffic - Highways in Space Figure 1 – High-altitude jetways

Air Traffic Control Figure 2a - Air Traffic Control Centers in the United States Figure 2b - Northern California Terminal Radar Approach Control

Continuous Descent Approach (CDA) Figure 3a - Continuous Descent Approach path Figure 3b - Today’s typical descent path Continuous Descent (Optimized Profile) Approach is assumed to reduce fuel burn and noise

Fuel Consumption Rate In Cruise Mode, fuel consumption rate decreases with increasing altitude Figure 4 - Fuel rate in kg/nmi for B737

Standard Arrival Approach Heterogeneous arrivals must be separated enough to land safely Altitude and speed are chosen based on a common subset of aircraft

Standard Arrival Routes Figure 5 - MOD3 STAR for SFO Airport

Analyzing Benefits of Continuous Descent Approach (CDA) Analysis Approach 1 Take current aircraft arrival trajectories 2 Move the constant altitude (Level) section to a high altitude Objective: Study fuel benefits of implementing CDA in the current airspace structure

Results on Airport Savings Airport Average (kg) Maximum (kg) TypeAnnual Savings $$ ATL33317B E+07 DFW38721MD117.75E+06 SFO881623B E+07 LAX20507B E+06 JFK40479B E+06 Scope of the Study 5 days of data for ATL, SFO, LAX airports 4 days of data for DFW, 1 day of data for JFK

Constant Altitude Segments of a Standard Arrival Route Figure 6 – Constant Altitude Segments for SFO MOD3 Arrival

Constant Altitude Segments Figure 7 – Atlanta ATL airport constant altitude level sections from four arrival posts Path extensions for separation result in constant altitude segments of arrival flight

Analysis of Results Implementing time-separation at higher altitudes would not improve fuel efficiency Figure 8 - Fuel rate kg/min for B737

Conclusions and Future Work Continuous Descent Approach in the current airspace restrictions will result on average savings of 50 kg fuel per flight Current descent approaches are based on air traffic needs for maintaining separation There is a trade-off between separation of aircraft and fuel savings that need to be analyzed

Current Research and Real-World Los Angeles LAX Louisville London Heathrow Airport

Atlanta ATL Airport Arrivals STARavg fuel (kg) avg time (min) number of aircraft FLCON CANUK HONIE ERLIN Arrivals from the East result in more fuel savings when arriving on the Westerly runways ERLINFLCON HONIECANUK Fuel Savings based on the Standard Arrival Route

Fuel Analysis Based on Routes and Runways Arrival towards East FLCON CANUKHONIE ERLIN Arrival towards West