Effect of Sustainable Aviation Fuels on Contrail Formation Across Flight Routes: A Thermodynamic Analysis

Authors

  • Zoya Sharma Liberal Arts and Science Academy, Austin, TX, United States of America

DOI:

https://doi.org/10.18192/osurj.v5i1.8091

Abstract

Aviation-induced contrail cirrus is known to be responsible for significant climate impact, yet fuel and engine-based mitigation strategies receive less emphasis than flight path and altitude optimization research. Flight path optimization studies require an enormous amount of multiparty coordination, real-time data collection, and resource-rich research partners. This study assesses the impact of sustainable aviation fuels (SAFs) on contrail formation, which is a research avenue more amenable to modeling. The usage of three SAF types, Hydroprocessed Esters and Fatty Acids Synthetic Paraffinic Kerosene (HEFA-SPK), Fischer-Tropsch Synthetic Paraffinic Kerosene (FT-SPK), and Alcohol-to-Jet Synthetic Paraffinic Kerosene (ATJ-SPK), was modeled on four representative flight routes. A mathematical framework based on the Schmidt-Appleman criterion (SAC) was developed. This framework was applied to atmospheric data at each waypoint along great circle routes for the four flight paths, enabling spatially resolved contrail formation probabilities to be evaluated for each fuel type. All three SAFs produced a marginal increase in mean contrail formation probability relative to baseline kerosene across all routes. This result is attributed to the higher water vapor emission indices and specific combustion heat of SAFs, which increase the slope parameter G and shift the threshold temperatures toward warmer values. However, this thermodynamic effect operates independently of the primary mitigatory mechanism of SAFs: the reduction of non-volatile particulate matter (nvPM) emissions. The reduced nvPM emissions suppress ice crystal nucleation through a distinct physical pathway not captured within the thermodynamic framework. The results therefore represent a worst-case estimate of contrail formation probability, and the full climate benefit of SAF deployment is expected to be realized when nvPM effects are incorporated alongside the thermodynamic assessment presented here.

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Published

2026-06-17

Issue

Section

Original Research