SAF (Sustainable Aviation Fuel)

SAF is a liquid fuel produced from non-petroleum feedstocks such as waste oil, non-food crops, and municipal waste that reduces CO2 emissions by up to 80% compared to conventional aviation fuel. SAF must have the same qualities and characteristics as conventional jet fuel and is entirely fungible with conventional kerosene requiring no adaptation of engines or associated delivery infrastructure. SAF can be blended at different levels with limits between 10% and 50%, depending on the feedstock and production pathway, with most approved pathways allowing up to 50% maximum blend ratios. SAF must meet ASTM D7566 specification requirements prior to blending with conventional Jet A fuel, after which the blended fuel is redesignated as meeting ASTM D1655 standard.

A FedEx Express cargo flight from Memphis (MEM) to Paris Charles de Gaulle (CDG) uses AWB number 023-45678901, where the aircraft is fueled with a 30% SAF blend meeting ASTM D1655 specification after the SAF component was certified under ASTM D7566. An Emirates SkyCargo Boeing 777F carrying AWB 176-87654321 from Dubai (DXB) to Frankfurt (FRA) operates on conventional Jet A fuel blended with 20% HEFA-SPK (Hydroprocessed Esters and Fatty Acids) SAF produced from waste cooking oil.

• sustainable aviation fuel
• bio jet fuel
• alternative aviation fuel
• SAF blending
• SAF mandate

What are the current maximum blending limits for SAF in commercial aviation?

SAF can be blended at different levels with limits between 10% and 50%, depending on the feedstock and production pathway, with most ASTM D7566 approved pathways allowing up to 50% maximum blend ratios. Co-processing pathways are limited to 5% blend ratios, while regulatory approval for 100% SAF use is expected by 2030 pending completion of material compatibility studies.

Which ASTM specifications govern SAF certification for air cargo operations?

SAF must meet ASTM D7566 Standard Specification for Aviation Turbine Fuel Containing Synthesized Hydrocarbons, and once blended with conventional fuel, the final product must meet ASTM D1655 Standard Specification for Aviation Turbine Fuels. There are currently 11 ASTM-approved SAF production pathways, with the HEFA (Hydroprocessed Esters and Fatty Acids) pathway expected to comprise 66% and AtJ (Alcohol-to-Jet) pathway 23% of 2030 SAF production.