ASTM D6227 Standard Specification for Grade 82 Unleaded Aviation Gasoline
4. Grades
4.1 The specification covers one grade of unleaded aviation gasoline designated Grade 82 UL. Grade 82 UL is the only aviation gasoline defined by this specification and the grade shows the minimum motor octane rating.
5. General
5.1 This specification, unless otherwise provided, prescribes the required properties of unleaded aviation gasoline at the time and place of delivery.
6. Material
6.1 Aviation gasoline, except as otherwise specified in this specification, shall consist of blends of refined hydrocarbons derived from crude petroleum, natural gasoline or blends, thereof, with specific aliphatic ethers, synthetic hydrocarbons, or aromatic hydrocarbons. When applicable, methyl tertiary-butyl ether (MTBE) shall conform to the requirements of Specification D5983. Types and quantities of trace alcohols shall meet the requirements of Table 1 and 6.2.4.2.
6.2 Only additives approved by this specification are permitted. In addition to identification dyes, corrosion inhibitors, antioxidants, and metal deactivators, fuel system icing inhibitor additives are permitted under 6.2.4. Permitted additives may be added to aviation gasoline in the amount and of the composition specified in the following list of approved materials.
6.2.1 Antioxidants - The following oxidation inhibitors may be added to the gasoline separately or in combination in total concentration not to exceed 12 mg of inhibitor (not including weight of solvent) per litre of fuel.
6.2.1.1 2,6 - ditertiary-butyl-phenol.
6.2.1.2 2,6 - ditertiary-butyl-4-methyl-phenol.
6.2.1.3 2,4 - dimethyl - 6 - tertiary-butyl - phenol.
6.2.1.4 2,6 - ditertiary - butyl - phenol, 75 % min.
Tertiary and tritertiary - butyl - phenols, 25 % max.
6.2.1.5 2,4-dimethyl-6-tertiary-butyl-phenol, 55 % min; 4-methyl-2,6-ditertiary-butyl phenol 15 % min; the remainder as a mixture of monomethyl and dimethyl-tertiary-butyl-phenols.
6.2.1.6 2,4 - dimethyl-6-tertiary-butyl-phenol, 72 % min.
Mixture of tertiary-butyl-methyl-phenols and tertiary-butyl-dimethyl-phenols, 28 % max.
6.2.1.7 2,6-ditertiary-butyl-4-methyl-phenol, 35 % min.
Mixed methyl, ethyl, and dimethyl tertiary-butyl-phenols, 65 % max
6.2.1.8 2,4-di-tertiary butyl-phenol, 60 % min.
Mixed tertiary-butyl-phenol, 40 % max.
6.2.1.9 Butylated ethyl-phenols, 55 % min.
Butylated methyl and dimethyl-phenols, 45 % max.
6.2.1.10 Mixture of a di- and tri-isopropyl-phenols, 75 % min.
Mixture of di- and tri-tertiary butyl-phenols, 25 % max.
6.2.1.11 N,N' di-secondary butyl-para phenylene diamine.
6.2.1.12 N,N' di-isopropyl-para-phenylene-diamine.
6.2.1.13 N-secondary butyl, N' - phenyl ortho - phenylene-diamine.
6.2.2 Metal Deactivators - A metal deactivator, N,N' - disalicylidene - 1,2- propane diamine may be added to the gasoline in an amount not to exceed 3.0 mg/L.
6.2.3 Corrosion Inhibitors - Corrosion inhibitors that conform to MIL-PRF-25017F may be added to the gasoline in amounts not exceeding the maximum allowable concentrations listed in the latest revision of QPL-25017.
6.2.4 Fuel System Icing Inhibitor:
6.2.4.1 Diethylene glycol monomethyl ether, conforming to the requirements of Specification D4171 (Type III), may be used in concentrations of 0.10 to 0.15 volume %.
6.2.4.2 Isopropyl alcohol conforming to the requirements of Specification D4171 (Type II) may be used in concentrations recommended by the aircraft manufacturers when required by the aircraft owner operator.
7. Detailed Requirements
7.1 The aviation gasoline shall conform to the requirements in Table 1.
8. Workmanship
8.1 The finished fuel shall be visually free of water, sediment, and suspended matter.
NOTE 1 - See Practice D4057 for appropriate sampling procedures.
