Feasibility test of per-flight contrail avoidance in commercial aviation

Contrails, formed by aircraft engines, are a major component of aviation’s impact on anthropogenic climate change. Contrail avoidance is a potential option to mitigate this warming effect, however, uncertainties surrounding operational constraints and accurate formation prediction make it unclear whether it is feasible. Here we address this gap with a feasibility test through a randomized controlled trial of contrail avoidance in commercial aviation at the per-flight level. Predictions for regions prone to contrail formation came from a physics-based simulation model and a machine learning model. Participating pilots made altitude adjustments based on contrail formation predictions for flights assigned to the treatment group. Using satellite-based imagery we observed 64% fewer contrails in these flights relative to the control group flights, a statistically significant reduction (p = 0.0331). Our targeted per-flight intervention allowed the airline to track their expected vs actual fuel usage, we found that there is a 2% increase in fuel per adjusted flight. This study demonstrates that per-flight detectable contrail avoidance is feasible in commercial aviation. Vapour trails (contrails) from aircraft make a substantial contribution to aviation’s climate impact. Here we execute a per-flight contrail avoidance feasibility test through altitude adjustments based on contrail formation predictions. The avoidance regime resulted in a 64% reduction in satellite-visible contrails at a 2% increase in fuel burn per adjusted flight.