Pinpointing Consumption “Sweet Spot” Makes Formation Flight More Fuel-Efficient

Formation flying — when one aircraft flies behind another — reduces drag and results in improved fuel consumption in the trailing vehicle; however, no sensor currently exists that directly measures drag. Instead, pilots rely on fuel flow measurements or induced aircraft moments — roll, pitch, and yaw — to estimate the best location within a leading vehicle's wave vortex. Fuel flow alone is a lagging drag estimate, which leads to inaccurate estimates. Aircraft moments alone also do not sufficiently indicate the best location for the trailing aircraft.