Fuel Efficient Air Traffic Control

Maryam Kamgarpour, PhD StudentClaire Tomlin, Research Adviser

John Robinson, NASA Ames Research CenterDecember 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 ofAir 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

Average fuel burn for new jet aircraft, 1960-2008

25

50

75

100

1960 1965 1970 1975 1980 1985 1990 1995 2000 2005

Year

Fu

el

bu

rn a

t d

esig

n r

an

ge

ton-km

seat-km

08

1960s

1970s

1980s

1990spost-2000

Annual Improvement Period Seat-km Ton-km 1960s 2.3% 3.6% 1970s 0.6% -0.1% 1980s 3.5% 2.5% 1990s 0.7% 0.9% post-2000 0.0% 0.3%

ICCT (2009). "Efficiency Trends for New Commercial Jet Aircraft, 1960 to 2008."

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 RateIn 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 Routes19000

18000

8000

7000

Figure 5 - MOD3 STAR for SFO Airport

Analyzing Benefits of Continuous Descent Approach (CDA)

Analysis Approach1 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

AirportAverage (kg)

Maximum (kg)

Type Annual Savings $$

ATL 33 317B763 1.18E+07

DFW 38 721MD11 7.75E+06SFO 88 1623B744 1.39E+07LAX 20 507B741 1.92E+06JFK 40 479B744 7.57E+06

Scope of the Study 5 days of data for ATL, SFO, LAX airports4 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

STAR avg fuel (kg)

avg time (min)

number of aircraft

FLCON 28 1.62 328CANUK 29 1.40 186HONIE 18 1.41 66ERLIN 13 0.81 249

Arrivals from the East result in more fuel savings when arriving on the Westerly runways

ERLIN FLCON

HONIE CANUK

Fuel Savings based on the Standard Arrival Route

Fuel Analysis Based on Routes and Runways

Arrival towards East

FLCON

CANUKHONIE

ERLIN

Arrival towards West