Sustainable air transportation through the operational use of a social cost index

Abstract

Air transportation is responsible for more than 10% of transportation related greenhouse gas emissions in the U.S. As policymakers and engineers search for methods to reduce aviation fuel consumption and the associated negative externalities, a metric used by aircrew on the flight deck may hold the key. The cost index metric and associated ECON speeds inputted into the flight management system control the aircraft's flying speed and ultimately the fuel consumed, and emissions produced. This study assesses the use of this operational tool to further green air transport production in U.S. domestic operations. Data from four major airline Boeing 737 NG routes are analyzed to estimate the effect of each carrier's cost index and ECON speeds on fuel consumption and emissions. Then a social cost index, which incorporates environmental costs, is estimated and tested using a Boeing 737 NG simulator across identical routes to determine the changes in fuel consumption and emissions. On average, we find that for every one unit decrease in an airline's cost index they reduce their fuel consumption by 5.37 lbs. per hour. Further, the average impact of implementing a social cost index is estimated to save nearly 22 gallons of jet fuel and reduce CO2 emissions by 453 lbs. per flight hour. These fuel and emissions reductions are estimated to generate a penalty of 1 min and 43 s on average per flight hour. Overall, we find that airlines can substantially reduce fuel consumption and emissions with minimal impact to operations via implementation of a social cost index.