Aircrafts flying around the world will be fueled at different airports in different countries which means that international fuel specifications for sustainable aviation fuels (SAF) is a necessity.
It’s a matter of ensuring flight safety and minimizing risk of mishandling, but it is also necessary to avoid the need for implementing a varied mix of fuel delivering systems at high cost. Finally, the specifications ensure that today’s engines or aircrafts does not have to be redesigned to run on SAF.
The standard regulating the technical certification of SAF is ASTM D7566 that specifies which technologies and methods can be used when producing on spec SAF. Once produced the SAF can then be blended up to a maximum certified blending limit and be certified to ASTM D1655 which is regarded as conventional Jet A or Jet A1 kerosene.