Full efficiency benefits and implementation considerations for cruise altitude and speed optimization in the National Airspace system

Abstract

This study examines the potential fuel burn benefits of altitude and speed optimization in the cruise phase of flight for domestic airlines in the United States. Airlines can achieve cost reductions and reduce environmental impact by making small modifications to the cruise phase operating condition. With strong coordination between air traffic controllers, pilots, and airline dispatchers, the efficiency of the National Airspace System can be improved. This study builds off of prior work in this area to establish best-case benefits assuming full implementation of fuel-optimal cruise altitudes and speeds. In order to achieve these objectives, a cruise-phase fuel burn estimator is developed using publicly-available radar tracks and weather data. This estimator is used to examine over 200,000 flights from 2012 for optimization potential. Maximum benefits from altitude optimization (holding speed constant) are found to be on the order 1.96% cruise fuel reduction. The incremental benefit of highfidelity trajectory optimization relative to well-designed step climb profiles indicates that the majority of potential altitude benefits can be achieved through efficient application of today's airspace structure and procedures. The maximum benefits for speed optimization (holding altitude constant) are found to be 1.94% with an average flight time increase of 3.5 minutes per flight. Simultaneous altitude and speed optimization yield a potential cruise fuel burn reduction of 3.71%. In practice, operational considerations and barriers to implementation limit likely system fuel reduction to lower levels. High-benefit operations within the NAS are identified and potential implementation considerations are discussed.