Aircraft Trajectory Design Based on Reducing the Combined Effects of Carbon-Di-Oxide, Oxides of Nitrogen and Contrails

Abstract

Aircraft operations need to meet the combined requirements of safety, efficiency, capacity and reduced environmental impact. Aircraft routes can be made efficient by flying wind optimal routes. However, the desire to reduce the impact of aviation emissions and contrails may result in trajectories, which deviate from wind optimal trajectories leading to extra fuel use. The lifetime associated with different emissions and contrails varies from a few hours to several hundred years. The impact of certain gases depends on the amount and location of the emission, and the decision-making horizon, in years, when the impact is estimated. The Absolute Global Temperature Potential (AGTP) is used as a metric to measure the combined effects of emissions and contrails. This paper extends earlier work by the authors to include the effect of oxides of nitrogen in the development of aircraft trajectories to reduce the combined effects of carbon dioxide, oxides of nitrogen (NO X ) and contrails. The methodology is applied to air traffic in the continental US. The paper shows the trade-offs between reducing emissions and the cost of extra fuel using a fuel sensitivity index, defined as the reduction in AGTP per kg of fuel. The paper shows the performance of the optimization strategy for decision intervals of 10, 25 and 100 years. Based on the simplified models, the inclusion of NO X emissions has a slight influence on the minimal climate impact trajectories when the decision horizons are around 25 years.

Identification of Flights for Cost-Efficient Climate Impact Reduction

“…23 Research in Ref. 6 shows NO X has relatively small effect for the climate reduction strategies compared to CO 2 and contrails, therefore its effect is ignored in this paper.…”

“…14 Using the coefficients described in Ref. 6, at the time horizon of H, Eq. (1) can be rewritten as…”

“…1 To address the aviation environment impacts with the growing air traffic, various methods have been proposed. [2][3][4][5][6] The largest environmental impacts for enroute air traffic comes from emissions of carbon-dioxide and nitrogen-oxides, and persistent contrail formations. It has been shown that commercial aircraft can reduce climate impact due to these factors by modifying their trajectories, although this often comes at the cost of increased fuel consumption.…”

Short/medium-term prediction for the aviation emissions in the en route airspace considering the fluctuation in air traffic demand

“…Then the fuel flow rate at the flight conditions is converted to the corresponding fuel flow rate at the reference conditions, i.e., ISA conditions at sea-level, according to Equations (6)(7)(8), and the reference fuel flow rate is 0.5080 kg/s. The emission indices and the fuel flow rates of a LTO cycle at the reference conditions for the engine V2500 are obtained from ICAO emission data bank as shown in Table 6, based on which the log-log relationship between EI and the fuel flow rate are developed in Fig.11-13.…”

“…The chemical and aerosol effects caused by aviation emissions contribute to the RF change, which ultimately results in the climate change [8][9] [10] . Therefore, this paper proposes to address the predicted effect of aviation emissions on climate change, which has not been studied before.…”