Commercial Airline Altitude Optimization Strategies for Reduced Cruise Fuel Consumption

The economic and environmental ramifications of aviation fuel burn are becoming increasingly more important for airlines, the traveling public, and society as a whole. Many methods are available for reducing fuel impacts. Airline operational adjustments are particularly appealing due to the potential for rapid implementation, significant savings, and relatively low capital expenditure requirements. One such mitigation is cruise speed and altitude optimization given a fixed lateral routing. This paper aims to establish an efficiency benefits pool for achievable systemwide cruise altitude optimization for domestic US operations. A flight-by-flight analysis is conducted using over 200,000 historical operations performed in 2012, accounting for actual winds and temperatures experienced by those flights. Various optimal altitude profiles are generated and compared to the as-flown baseline. A discussion of barriers to implementation accompanies these results. From this analysis, potential systemwide fuel burn reductions of 1.87% (cruise climb), 1.91% (1,000 ft. step climb), 1.75% (2,000 ft. step climb), and 1.96% (flexible climb/descent profiles) are shown to be possible through optimal altitude selection, holding lateral track and speed profiles constant relative to historical records. The comparative benefits of altitude and speed optimization are discussed.