The contrail mitigation potential of aircraft formation flight scenarios

Abstract

Extended formation flight (with separations of 10 to 40 wing spans) is a viable option to increase the performance of the commercial aviation sector. Fuel savings of around 10% can be expected during such formations (on average over all participating aircraft), which must substantially outweigh re-routing induced fuel penalty. Net fuel savings directly translate into lower CO2 emissions. Moreover, saturation effects can be expected when contrails of two or more aircraft are produced in close proximity, compete for the available atmospheric water vapour and mutually nhibit their growth. High-resolution simulations of contrails with a well-established model are presented and quantify those saturation effects by comparing long-living contrails behind a two aircraft formation with those evolving behind a single aircraft. The simulations suggest that radiatively-important contrail properties are reduced by 20%-60%. The simulations were performed within the FORMIC project, which also quantified the saturation effects on a regional scale due to non-linear chemistry and the change in the overall global climate impact by the introduction of formation flight (see extended abstract by Dahlmann) and according changes in the flight route cadastre (see also extended abstract by Marks et al).