ASTM D7566 for Aviation Turbine Fuel Containing Synthesized Hydrocarbons
3. General
3.1 This specification, unless otherwise provided, prescribes the required properties of aviation turbine fuel at the time and place of batch origination.

4. Terminology
4.1 Definitions:
4.1.1 conventional hydrocarbons, n - hydrocarbons derived from the following conventional sources: crude oil, natural gas liquid condensates, heavy oil, shale oil, and oil sands.

4.2 Definitions of Terms Specific to This Standard:
4.2.1 batch origination, n - location at which fuel is certified as D7566.

4.2.2 conventional blending component, n - blending streams derived from conventional hydrocarbons.

4.2.3 hydroprocessed, adj - conventional chemical processing in which hydrogen is reacted with organic compounds in the presence of a catalyst to remove impurities such as oxygen, sulfur, nitrogen; to saturate unsaturated hydrocarbons; or to alter the molecular structure of the hydrocarbon molecules.

4.2.4 synthesized hydrocarbons, n - hydrocarbons derived from alternative sources such as coal, natural gas, biomass, and hydrogenated fats and oils by processes such as gasification, Fischer-Tropsch synthesis, and hydroprocessing.

4.2.5 synthetic blending component, n - synthesized hydrocarbons that meet the requirements of Annex A1, Annex A2, or Annex A3.

4.2.6 synthesized iso-paraffins (SIP), n - synthetic blending component that is comprised essentially of iso-paraffins.

4.2.7 synthesized paraffinic kerosine (SPK), n - synthetic blending component that is comprised essentially of isoparaffins, normal paraffins, and cycloparaffins.
4.2.7.1 Discussion - Trace materials are permitted provided they are components that normally occur in hydroprocessed jet fuel including, but not limited to, trace organics, nitrogen compounds, water, dissolved air, etc.

5. Classification
5.1 Two grades of aviation turbine fuels are provided, as follows:
5.1.1 Jet A and Jet A-1 - Relatively high flash point distillates of the kerosine type.

5.2 Jet A and Jet A-1 represent two grades of kerosine fuel that differ in freezing point. Other grades would be suitably identified.

6. Materials and Manufacture
6.1 Aviation turbine fuel, except as otherwise defined in this specification, shall consist of the following blends of components or fuels:
6.1.1 Conventional blending components or Jet A or Jet A-1 fuel certified to Specification D1655; with up to 50 % by volume of the synthetic blending component defined in Annex A1.

6.1.2 Conventional blending components or Jet A or Jet A-1 fuel certified to Specification D1655; with up to 50 % by volume of the synthetic blending component defined in Annex A2.

6.1.3 Conventional blending components or Jet A or Jet A-1 fuel certified to Specification D1655; with up to 10 % by volume of the synthetic blending component defined in Annex A3.

NOTE 1 - The ability to add 50 % of Annex A1 or Annex A2 blending components (SPK) to Jet A or Jet A-1 is also limited by the physical properties of the fuel with which it is being blended. Practice has shown that density, or aromatic content, or both, of the refined fuel often limit the amount of SPK that can be added to the final blend to less than 50 %.

NOTE 2 - The ability to add 10 % of Annex A3 blending components (SIP) to Jet A or Jet A-1 may also be limited by the physical properties of the fuel with which it is being blended. It is possible in extreme cases that viscosity of the refined fuel may limit the amount of SIP that can be added to the final blend to less than 10 %.

6.2 Fuels used in certified engines and aircraft are ultimately approved by the certifying authority subsequent to formal submission of evidence to the authority as part of the type certification program for that aircraft and engine model. Additives to be used as supplements to an approved fuel must also be similarly approved on an individual basis (see X1.2.4).

6.3 Additives - May be added to each type of aviation turbine fuel in the amount and of the composition specified in Tables 1 and 2 or the following list of approved material:
6.3.1 Other additives are permitted under 6.2 and 8.1. These include fuel performance enhancing additives and fuel handling and maintenance additives as found under Table 2. The quantities and types shall be declared by the fuel supplier and agreed to by the purchaser. Only additives approved by the aircraft and engine certifying authorities are permitted in the fuel on which an aircraft is operated.
6.3.1.1 Biocidal additives are available for controlled usage. Where such an additive is used in the fuel, the approval status of the additive and associated conditions shall be checked for the specific aircraft and engines to be operated.

6.3.1.2 Fuel System Icing Inhibitor:
(1) Diethylene Glycol Monomethyl Ether (DiEGME), conforming to the requirements of Specification D4171, Type III, may be used in concentrations of 0.10 % to 0.15 % by volume.
(2) Test Method D5006 may be used to determine the concentration of DiEGME in aviation fuels.

6.4 Guidance material is presented in Appendix X3 concerning the need to control processing additives in jet fuel production.

6.5 From the point of manufacture to the point of blending to meet this specification, the synthetic blending component shall be handled and transported in the same manner as finished jet fuel in order to maintain product integrity. Appropriate management of change measures shall be used at manufacturing locations, distribution, and storage to maintain product integrity (see Appendix X3).