Effect of Climb Angle on Aircraft Fuel Consumption and Nitrogen Oxides Emissions

Abstract

Departure climb angles differ with respect to factors such as obstacles within the departure track, meteorological conditions, and cost index input, most of which have a dynamic nature to some extent. In this sense, it is relevant to perform parametric analyses to capture the outcomes of various climb angles. Therefore, in this Paper, the effects of the departure climb angle, mainly on fuel consumption and nitrogen oxides emissions, are quantified for an increment level as low as 0.25 deg of the departure climb angle. Using actual flight data of a large number of flights, the impacts of climb angle variations are statistically analyzed. The fuel burn and nitrogen oxides emissions tend to increase by 9-19 kg and 0.3-0.7 kg per degree of climb angle for the departure climb phase between takeoff and a further 5 n mile horizontal distance. Furthermore, this trend is a function of aircraft mass, which leads to a similar to 2% (fuel burn) and a similar to 5% (nitrogen oxides) increase for each 2 ton increase in aircraft mass. The current Paper also investigates the effects of the average climb angle in a broader sense, associated with cruise flights. Applying a steeper average climb angle during climb to 30,000 ft, the marginal reductions in fuel burn and nitrogen oxides are found to be 157 and 3.4 kg, whereas they are 65 and 3 kg for the combined climb and cruise phases, respectively.