ASTM D7719-21a

Standard Specification for High Aromatic Content Unleaded Hydrocarbon Aviation Gasoline Test Fuel

ABSTRACT
This specification covers formulating specifications for purchases of a high octane unleaded test fuel under contract and is intended solely for use by purchasing agencies for testing purposes. This specification also defines a specific type of high octane unleaded test fuel for use as an aviation spark-ignition fuel. A new high-octane unleaded test fuel has been developed, which maintains the key performance parameters of existing reciprocating aircraft engines.
SCOPE
1.1 This specification covers formulating specifications for purchases of a high aromatic content unleaded hydrocarbon aviation gasoline test fuel under contract and is intended solely for use by purchasing agencies for testing purposes.2  
1.2 This specification defines a specific type of high aromatic content unleaded hydrocarbon aviation gasoline (hereafter also referred to as “D7719 fuel”) for use as an aviation spark-ignition test fuel. It does not include all fuels satisfactory for reciprocating aviation engines. Certain equipment or conditions of use may permit a wider, or require a narrower, range of characteristics than is shown by this specification.  
1.3 The D7719 fuel defined by this specification does not exhibit identical performance to those leaded fuels for which the existing aircraft and ground-based fuel handling equipment have been designed to operate on. Therefore, the suitability of this test fuel for use on any specific aircraft, aircraft engine, or ground-based fuel handling equipment should be evaluated before use on that equipment.  
1.4 Issuance of this specification does not constitute approval to operate certificated aircraft with this fuel. 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 certification program for that aircraft and engine model.  
1.5 This specification, unless otherwise provided, prescribes the required properties of unleaded D7719 test fuel at the time and place of delivery.  
1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Jun-2021
• ICS: 75.160.20 - Liquid fuels
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.J0.02 - Aviation Piston Engine Fuels

Relations

• Refers: ASTM D2700-24 - Standard Test Method for Motor Octane Number of Spark-Ignition Engine Fuel
• Effective Date: 01-Mar-2024
• Refers: ASTM D910-24 - Standard Specification for Leaded Aviation Gasolines
• Effective Date: 01-Mar-2024
• Refers: ASTM D1094-24 - Standard Test Method for Water Reaction of Aviation Fuels
• Effective Date: 01-Mar-2024
• Refers: ASTM D3606-24 - Standard Test Method for Determination of Benzene and Toluene in Spark Ignition Fuels by Gas Chromatography
• Effective Date: 01-Mar-2024
• Refers: ASTM D4814-24 - Standard Specification for Automotive Spark-Ignition Engine Fuel
• Effective Date: 01-Jan-2024
• Refers: ASTM D86-23a - Standard Test Method for Distillation of Petroleum Products and Liquid Fuels at Atmospheric Pressure
• Effective Date: 01-Dec-2023
• Refers: ASTM D4814-23a - Standard Specification for Automotive Spark-Ignition Engine Fuel
• Effective Date: 01-Dec-2023
• Refers: ASTM D86-23ae1 - Standard Test Method for Distillation of Petroleum Products and Liquid Fuels at Atmospheric Pressure
• Effective Date: 01-Dec-2023
• Refers: ASTM D2700-23b - Standard Test Method for Motor Octane Number of Spark-Ignition Engine Fuel
• Effective Date: 01-Nov-2023
• Refers: ASTM D4865-23 - Standard Guide for Generation and Dissipation of Static Electricity in Petroleum Fuel Systems
• Effective Date: 01-Nov-2023
• Refers: ASTM D7826-23b - Standard Guide for Evaluation of New Aviation Gasolines and New Aviation Gasoline Additives
• Effective Date: 01-Nov-2023
• Refers: ASTM D2700-23a - Standard Test Method for Motor Octane Number of Spark-Ignition Engine Fuel
• Effective Date: 01-Oct-2023
• Refers: ASTM D4814-20 - Standard Specification for Automotive Spark-Ignition Engine Fuel
• Effective Date: 01-Feb-2020
• Refers: ASTM D910-19 - Standard Specification for Leaded Aviation Gasolines
• Effective Date: 01-Dec-2019
• Refers: ASTM D4814-19a - Standard Specification for Automotive Spark-Ignition Engine Fuel
• Effective Date: 01-Dec-2019

Overview

ASTM D7719-21a: Standard Specification for High Aromatic Content Unleaded Hydrocarbon Aviation Gasoline Test Fuel establishes requirements for a specialized, high octane, unleaded hydrocarbon aviation gasoline. The standard is designed explicitly for the procurement and testing of this fuel type by purchasing agencies. The specification, known as D7719 fuel or UL102, ensures that performance-relevant properties are maintained for testing spark-ignition aviation engines, particularly in circumstances where unleaded high aromatic content is required.

Unlike conventional leaded aviation fuels, D7719 fuel supports efforts to reduce toxic emissions and enables research, compatibility evaluations, and development for unleaded solutions in aviation. This standard is not intended for actual in-flight use in certified aircraft unless subsequently approved by the relevant certifying authorities.

Key Topics

• Scope of Use
  The D7719 specification applies exclusively to the procurement and testing of high aromatic content, unleaded hydrocarbon aviation gasoline for spark-ignition aircraft engines. It is not intended as a blanket specification for all aviation fuels or operational use in certificated aircraft without further certification.

• Performance Characteristics
  D7719 fuel is defined by its high octane rating (minimum Motor Octane Number 102.2), elevated aromatic content (minimum 70% by mass), and absence of intentionally added lead. The fuel delivers operational properties, such as volatility, density, and net heat of combustion, intended to ensure reliable engine performance during testing.

• Quality and Purity
  The standard mandates that D7719 fuel be free from harmful levels of impurities, water, sediment, and other contaminants. Only specified additives and dyes are allowed, with clear limitations to their concentration, to maintain consistency in fuel characteristics and safety during use.

• Additives
  Permitted additives include approved antioxidants, dyes, corrosion inhibitors, fuel system icing inhibitors, and electrical conductivity agents. All additives must be declared by the manufacturer and conform to specified limits, supporting safe test conditions and fuel system integrity.

• Testing and Sampling
  Comprehensive ASTM test methods are referenced for verifying critical properties such as octane number, distillation characteristics, vapor pressure, sulfur content, freezing point, and corrosion potential. Sampling protocols emphasize contamination control to ensure reliable test results.

Applications

• Engine and Component Testing
  D7719 fuel is primarily used for laboratory, ground, and possibly flight test environments to evaluate the performance and durability of existing or new aircraft engine designs intended for unleaded, high aromatic content fuel.

• Procurement and Evaluation
  The specification provides a contractual basis for agencies and organizations to acquire high aromatic unleaded aviation gasoline for controlled testing environments, aiding research in unleaded fuel options for the aviation sector.

• Compatibility Assessments
  The standard supports material compatibility, toxicology, and system performance evaluations, which are critical prior to the introduction of unleaded aviation fuels in wider operational use.

• Regulatory and Certification Support
  D7719 may be referenced in demonstrating evidence for certification programs, although actual operational approval for use in certified aircraft requires separate authorizations from aviation authorities.

Related Standards

Several ASTM standards are referenced within ASTM D7719-21a to support comprehensive testing and specification conformance:

• ASTM D910: Specification for Leaded Aviation Gasolines
• ASTM D4052: Test Method for Density and API Gravity of Liquids
• ASTM D2700: Test Method for Motor Octane Number
• ASTM D86: Distillation of Petroleum Products
• ASTM D4809: Measurement of Heat of Combustion
• ASTM D2622, D4294, D7220: Sulfur in Petroleum Products
• ASTM D2386: Determination of Freezing Point

For a full list of referenced methods, consult the ASTM D7719-21a document.

---

By specifying the necessary properties and test requirements for high aromatic content unleaded hydrocarbon aviation gasoline, ASTM D7719-21a supports the ongoing transition towards unleaded fuels in aviation, facilitating safe and controlled research, procurement, and evaluation activities across the sector.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation:D7719 −21a
Standard Specification for
High Aromatic Content Unleaded Hydrocarbon Aviation
Gasoline Test Fuel
This standard is issued under the fixed designation D7719; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* 1.7 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This specification covers formulating specifications for
responsibility of the user of this standard to establish appro-
purchases of a high aromatic content unleaded hydrocarbon
priate safety, health, and environmental practices and deter-
aviationgasolinetestfuelundercontractandisintendedsolely
2 mine the applicability of regulatory limitations prior to use.
for use by purchasing agencies for testing purposes.
1.8 This international standard was developed in accor-
1.2 This specification defines a specific type of high aro-
dance with internationally recognized principles on standard-
matic content unleaded hydrocarbon aviation gasoline (hereaf-
ization established in the Decision on Principles for the
ter also referred to as “D7719 fuel”) for use as an aviation
Development of International Standards, Guides and Recom-
spark-ignitiontestfuel.Itdoesnotincludeallfuelssatisfactory
mendations issued by the World Trade Organization Technical
for reciprocating aviation engines. Certain equipment or con-
Barriers to Trade (TBT) Committee.
ditions of use may permit a wider, or require a narrower, range
of characteristics than is shown by this specification. 2. Referenced Documents
2.1 ASTM Standards:
1.3 The D7719 fuel defined by this specification does not
exhibit identical performance to those leaded fuels for which D86Test Method for Distillation of Petroleum Products and
Liquid Fuels at Atmospheric Pressure
theexistingaircraftandground-basedfuelhandlingequipment
have been designed to operate on. Therefore, the suitability of D130Test Method for Corrosiveness to Copper from Petro-
leum Products by Copper Strip Test
this test fuel for use on any specific aircraft, aircraft engine, or
ground-based fuel handling equipment should be evaluated D323TestMethodforVaporPressureofPetroleumProducts
(Reid Method)
before use on that equipment.
D873Test Method for Oxidation Stability ofAviation Fuels
1.4 Issuance of this specification does not constitute ap-
(Potential Residue Method)
proval to operate certificated aircraft with this fuel. Fuels used
D909TestMethodforSuperchargeRatingofSpark-Ignition
in certified engines and aircraft are ultimately approved by the
Aviation Gasoline
certifying authority subsequent to formal submission of evi-
D910Specification for Leaded Aviation Gasolines
dence to the authority as part of the certification program for
D1094Test Method for Water Reaction of Aviation Fuels
that aircraft and engine model.
D1266TestMethodforSulfurinPetroleumProducts(Lamp
1.5 Thisspecification,unlessotherwiseprovided,prescribes
Method)
the required properties of unleaded D7719 test fuel at the time
D1298Test Method for Density, Relative Density, or API
and place of delivery.
Gravity of Crude Petroleum and Liquid Petroleum Prod-
ucts by Hydrometer Method
1.6 The values stated in SI units are to be regarded as
D2386Test Method for Freezing Point of Aviation Fuels
standard. No other units of measurement are included in this
D2622Test Method for Sulfur in Petroleum Products by
standard.
Wavelength Dispersive X-ray Fluorescence Spectrometry
D2624Test Methods for Electrical Conductivity ofAviation
and Distillate Fuels
This specification is under the jurisdiction of ASTM Committee D02 on
D2700Test Method for Motor Octane Number of Spark-
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Ignition Engine Fuel
Subcommittee D02.J0.02 on Aviation Piston Engine Fuels.
Current edition approved July 1, 2021. Published August 2021. Originally
approved in 2011. Last previous edition approved in 2021 as D7719–21. DOI:
10.1520/D7719-21A. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Supporting data have been filed atASTM International Headquarters and may contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
beobtainedbyrequestingResearchReportRR:D02-1721.ContactASTMCustomer Standards volume information, refer to the standard’s Document Summary page on
Service at [e-mail]. the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7719−21a
D3237TestMethodforLeadinGasolinebyAtomicAbsorp- ignition engines, where lead and lead-containing compounds
tion Spectroscopy arenotintentionallyaddedforthepurposeofenhancingoctane
D3606Test Method for Determination of Benzene and performanceandwhichexcludesnon-hydrocarbons,exceptfor
Toluene in Spark Ignition Fuels by Gas Chromatography additives approved in this specification.
D4052Test Method for Density, Relative Density, and API
Gravity of Liquids by Digital Density Meter 4. General
D4057Practice for Manual Sampling of Petroleum and
4.1 Thisspecification,unlessotherwiseprovided,prescribes
Petroleum Products
the required properties of a high aromatic content unleaded
D4171Specification for Fuel System Icing Inhibitors
hydrocarbonaviationgasolinetestfuelatthetimeandplaceof
D4177Practice for Automatic Sampling of Petroleum and
delivery.
Petroleum Products
D4294Test Method for Sulfur in Petroleum and Petroleum
5. Classification
Products by Energy Dispersive X-ray Fluorescence Spec-
5.1 One grade of high aromatic content unleaded hydrocar-
trometry
bon aviation gasoline is provided, known as UL102.
D4306Practice for Aviation Fuel Sample Containers for
Tests Affected by Trace Contamination
6. Materials and Manufacture
D4809Test Method for Heat of Combustion of Liquid
Hydrocarbon Fuels by Bomb Calorimeter (Precision
6.1 D7719 fuel, except as otherwise specified in this
Method)
specification, shall consist of blends of refined hydrocarbons.
D4814Specification for Automotive Spark-Ignition Engine
The sources for these hydrocarbons include biomass, natural
Fuel
gas, or crude petroleum.
D4865Guide for Generation and Dissipation of Static Elec-
6.1.1 See Appendix X1 for one particular composition that
tricity in Petroleum Fuel Systems
meets the parameters of Table 1.
D5006Test Method for Measurement of Fuel System Icing
6.2 Additives—These can be added to each grade of D7719
Inhibitors (Ether Type) in Aviation Fuels
fuel in the amount, and of the composition, specified in the
D5059Test Methods for Lead and Manganese in Gasoline
following list of approved materials:
by X-Ray Fluorescence Spectroscopy
6.2.1 Dyes—Thetotalmaximumconcentrationofdyeinthe
D5191Test Method for Vapor Pressure of Petroleum Prod-
fuel is 6.0 mg/L. (See X1.1.1 and X2.2.7.)
ucts and Liquid Fuels (Mini Method)
6.2.1.1 The only blue dye present in the finished fuel shall
D5580Test Method for Determination of Benzene,Toluene,
be essentially 1,4-dialkylaminoanthraquinone.
Ethylbenzene, p/m-Xylene, o-Xylene, C and Heavier
6.2.1.2 The only yellow dyes in the finished fuel shall be
Aromatics, and Total Aromatics in Finished Gasoline by
essentially p-diethylaminoazobenzene (Color Index No.
Gas Chromatography
11021) or 1,3-benzenediol 2,4-bis [(alkylphenyl)azo-].
D6469GuideforMicrobialContaminationinFuelsandFuel
6.2.1.3 Theonlyreddyepresentinthefinishedfuelshallbe
Systems
essentially alkyl derivatives of azobenzene-4-azo-2-naphthol.
D6733Test Method for Determination of Individual Com-
6.2.1.4 Theonlyorangedyepresentinthefinishedfuelshall
ponents in Spark Ignition Engine Fuels by 50-Metre
beessentiallybenzene-azo-2-napthol(ColorIndexNo.12055).
Capillary High Resolution Gas Chromatography
6.2.2 Other Additives—These may be added in the amount
D7220Test Method for Sulfur in Automotive, Heating, and
and of the composition specified in the following list of
Jet Fuels by Monochromatic Energy Dispersive X-ray
approved materials. The quantities and types shall be declared
Fluorescence Spectrometry
by the manufacturer. Additives added after the point of
D7826Guide for Evaluation of NewAviation Gasolines and
manufacture shall also be declared.
New Aviation Gasoline Additives
6.2.2.1 Antioxidants—The following oxidation inhibitors
E29Practice for Using Significant Digits in Test Data to
may be added to the fuel separately, or in combination, in total
Determine Conformance with Specifications
concentration not to exceed 12 mg of inhibitor (not including
3. Terminology
weight of solvent) per litre of fuel.
(1)2,6-ditertiary butyl-4-methylphenol.
3.1 Definitions:
(2)2,4-dimethyl-6-tertiary butylphenol.
3.1.1 binary, adj—characterized by, or consisting of, two
(3)2,6-ditertiary butylphenol.
components.
(4)75 % minimum 2,6-ditertiary butylphenol plus 25 %
3.1.2 biomass, n—biological material including any mate-
maximum mixed tertiary and tritertiary butylphenols.
rial other than fossil fuels which is or was a living organism or
(5)75%minimumdi-andtri-isopropylphenolsplus25%
component or product of a living organism.
maximum di- and tri-tertiary butylphenols.
3.1.3 non-hydrocarbon, n—compound or compounds com-
(6)72 % minimum 2,4-dimethyl-6-tertiary butylphenol
posedofcarbon,hydrogen,andotherelementssuchasoxygen,
plus 28 % maximum monomethyl and dimethyl tertiary butyl-
nitrogen, sulfur, and phosphorus.
phenols.
3.1.4 unleaded hydrocarbon aviation gasoline, n—gasoline (7)N,N’-di-isopropyl-para-phenylenediamine.
intended for use in aircraft powered by reciprocating spark- (8)N,N’-di-secondary-butyl-para-phenylenediamine.
D7719−21a
A
TABLE 1 Detailed Requirements for HighAromatic Content Unleaded HydrocarbonAviation Gasoline Test Fuel
B
Grade UL102 ASTM Test Method
Property
COMBUSTION
Octane Rating min 102.2 D2700
C
Knock value, Motor Octane Number
Net heat of combustion, MJ/kg min 41.5 D4809
COMPOSITION
Sulfur, mass % max 0.05 D1266, D2622, D4294,or D7220
Tetraethyl Lead, g Pb/L max 0.013 D3237 or D5059
Total Aromatics, % (m/m)min 70 D6733
D
Benzene, % (m/m) max 0.1 D3606 or D5580
Requirements for All Grades
VOLATILITY
Vapor pressure, 37.8 °C, kPa min 38.0
E
D323 or D5191
max 49.0
Density at 15 °C, kg/m min 790
D1298 or D4052
max 825
Distillation D86
Initial boiling point, °C Report D86
Fuel Evaporated D86
10 volume % at °C max 75 D86
40 volume % at °C min 75 D86
50 volume % at °C max 165 D86
90 volume % at °C max 165 D86
Final boiling point, °C max 180 D86
Sum of 10%+50% evaporated temperatures, °C min 135 D86
Recovery, volume % min 97 D86
Residue, volume % max 1.5 D86
Loss, volume % max 1.5 D86
FLUIDITY
F
Freezing point, °C max –58 D2386
CORROSION
Copper strip, 2 h at 100 °C max No. 1 D130
CONTAMINANTS
G
Oxidation stability (5 h aging)
D873
Potential gum, mg/100 mL max 6
Water reaction
D1094
Volume change, mL max ±2
OTHER
H
Electrical conductivity, pS/m max 600 D2624
A
For compliance of test results against the requirements of Table 1, see 7.2.
B
The test methods indicated in this table are referred to in Section 11.
C
Knock ratings shall be reported to the nearest 0.1 octane number.
D
In case of dispute, Test Method D3606 shall be used as the referee method.
E
Test Method D5191 shall be the referee vapor pressure method.
F
If no crystals have appeared on cooling to –58 °C, the freezing point may be reported as less than –58 °C.
G
If mutually agreed upon between the purchaser and the supplier, a 16 h aging gum requirement may be specified instead of the 5 h aging gum test; in such case the
gum content shall not exceed 10 mg ⁄100 mL. In such fuel the permissible antioxidant shall not exceed 24 mg ⁄L.
H
Applies only when an electrical conductivity additive is used; when a customer specifies fuel containing conductivity additive, the following conductivity limits shall apply
under the condition at point of use:
Minimum 50 pS ⁄m
Maximum 600 pS ⁄m.
The supplier shall report the amount of additive added.
below minimum specification values. See X2.2.3.
6.2.2.2 Fuel System Icing Inhibitor (FSII)—One of the
following materials may be used:
6.2.2.3 Electrical Conductivity Additive—Stadis® 450 in
(1)Isopropyl Alcohol (IPA, propan-2-ol), in accordance
concentrations up to 3 mg/L is permitted. When loss of fuel
with the requirements of Specification D4171 (Type II). May
conductivitynecessitatesretreatmentwithelectricalconductiv-
be used in concentrations recommended by the aircraft manu-
ity additive, further addition is permissible up to a maximum
facturer when required by the aircraft owner/operator.
cumulative level of 5mg⁄L of Stadis® 450.
(2)Di-Ethylene Glycol Monomethyl Ether (Di-EGME),
6.2.2.4 Corrosion Inhibitor Additive—The following corro-
conforming to the requirements of Specification D4171 (Type
sion inhibitors may be added to the fuel in concentrations not
III). May be used in concentrations of 0.10% to 0.15% by
to exceed the maximum allowable concentration (MAC) listed
volume when required by the aircraft owner/operator.
for each additive.
(3)Test Method D5006 can be used to determine the
concentration of Di-EGME in aviation fuels.
Stadis® 450 is a registered trademark marketed by Innospec, Inc., Innospec
NOTE1—Additionofisopropylalcohol(IPA)mayreduceknockratings Manufacturing Park, Oil Sites Road, Ellesmere Port, Cheshire, CH65 4EY, UK.
D7719−21a
to trace contamination which can originate from sample
DCI-4A MAC = 24.0 g/m
DCI-6A MAC = 15.0 g/m
containers. For recommended sample containers, refer to
HITEC 580 MAC = 22.5 g/m
Practice D4306.
NALCO 5403 MAC = 22.5 g/m
NALCO 5405 MAC = 11.0 g/m
3 10. Reports
UNICOR J MAC = 22.5 g/m
SPEC-AID 8Q22 MAC = 24.0 g/m
10.1 Thetypeandnumberofreportstoensureconformance
TOLAD 351 MAC = 24.0 g/m
3 with the requirements of this specification shall be mutually
TOLAD 4410 MAC = 22.5 g/m
agreed to by the purchaser and the supplier of the D7719 fuel.
7. Detailed Requirements
11. Test Methods
7.1 The D7719 fuel shall conform to the requirements
11.1 Therequirementsenumeratedinthisspecificationshall
prescribed in Table 1.
be determined in accordance with the following ASTM test
methods:
7.2 Test results shall not exceed the maximum or be less
11.1.1 Knock Value (Motor Octane Number)—Test Method
than the minimum values specified in Table 1. No allowance
D2700.
shall be made for the precision of the test methods. To
11.1.2 Tetraethyl Lead—Test Methods D3237 or D5059.
determine the conformance to the specification requirement, a
11.1.3 Density—Test Methods D1298 or D4052.
test result may be rounded to the same number of significant
11.1.4 Distillation—Test Method D86.
figures as in Table 1 using Practice E29. Where multiple
11.1.5 Freezing Point—Test Method D2386.
determinationsaremade,theaverageresult,roundedaccording
11.1.6 Vapor Pressure—Test Methods D323 or D5191.
to Practice E29, shall be used.
11.1.7 Net Heat of Combustion—Test Method D4809.
11.1.8 Sulfur—Test Methods D1266, D2622, D4294,or
8. Workmanship, Finish, and Appearance
D7220.
8.1 The D7719 fuel specified in this specification shall be
11.1.9 Corrosion (Copper Strip)—Test Method D130,2h
free from undissolved water, sediment, and suspended matter.
test at 100°C in bomb.
No substances of known dangerous toxicity, under usual
11.1.10 Potential Gum and Visible Lead Precipitate—Test
conditions of handling and use, shall be present except as
Method D873 except that wherever the letter X occurs (refer-
permitted in this specification.
ring to oxidation time) insert the number 5, designating the
number of hours prescribed in this specification.
9. Sampling
11.1.11 Water Reaction—Test Method D1094.
9.1 Because of the importance of proper sampling proce- 11.1.12 Electrical Conductivity—Test Method D2624.
dures in establishing fuel quality, use the appropriate proce- 11.1.13 Aromatic Content—Test Method D6733.
dures in Practice D4057 or Practice D4177. 11.1.14 Benzene Content—Test Methods D3606 or D5580.
9.1.1 Although automatic sampling following Practice
12. Keywords
D4177maybeusefulincertainsituations,initialmanufacturer/
12.1 aviation gasoline; binary; hydrocarbon; unleaded
supplierspecificationcompliancetestingshallbeperformedon
a sample taken following procedures in Practice D4057.
Supporting data have been filed atASTM International Headquarters and may
9.2 A number of D7719 fuel properties, including copper
beobtainedbyrequestingResearchReportRR:D02-1808.ContactASTMCustomer
corrosion, electrical conductivity, and others are very sensitive Service at [e-mail].
APPENDIXES
(Nonmandatory Information)
X1. HIGH AROMATIC CONTENT BINARY UNLEADED HYDROCARBON AVIATION GASOLINE COMPOSITION
X1.1 Introduction unintentionalcontaminationbyTEL.Lastly,referencestodyes
remain in the specification so that test groups may use them as
X1.1.1 Anew high aromatic content unleaded hydrocarbon
necessary. This specification covers a high-octane unleaded
aviation gasoline has been developed for reciprocating aircraft
hydrocarbon aviation gasoline developed for existing spark-
engines. The two essential performance parameters of MON
ignition aircraft engines.
and VP are inversely related with respect to composition and
thus can uniquely define a composition range of the two
X1.2 Composition
components.ThevaluesforVPandMONinTable1reflectthe
limiting values of the two components.The distillation param- X1.2.1 The origin of the fuel lies in two essential engine
eters reflect the binary compositional effects. This is an performance parameters: Motor Octane Number, and Vapor
unleaded fuel, so the limit of TEL in Table 1 is the same as is Pressure.Fig.X1.1showstheinverserelationshipofthesetwo
usedinSpecificationD4814formogasandismeanttomitigate parameters as a function of mesitylene composition.
D7719−21a
FIG. X1.1Motor Octane Number and Vapor Pressure versus % Mesitylene
X1.2.2 These two parameters coupled with the fact that the (2)High Limit Reid Composition 79% mesitylene 21%
fuel is a binary composition, fix the effective composition
isopentane
range as follows:
X1.2.3 These limits are proposed to define the binary fuel’s
(1)High-Octane Composition: 84% mesitylene 16% iso-
specification composition.
pentane
D7719−21a
X2. PERFORMANCE CHARACTERISTICS OF HIGH AROMATIC CONTENT UNLEADED HYDROCARBON AVIATION
GASOLINE
X2.1 Introduction take-off, climb and cruise conditions. Leaded aviation gaso-
lines also specify the Test Method D909 Supercharge Rating,
X2.1.1 High aromatic content unleaded hydrocarbon avia-
but this method is not currently specified in Table 1 for D7719
tion gasoline (hereafter referred to as “D7719 fuel”) is a
fuel because it produces an atypical response compared to the
mixture of hydrocarbons that result in a narrow range of
leadedreferencefuelsusedinthemethod.Researchisongoing
physical and chemical properties to assure an appropriate
to determine if an alternative Supercharge Rating method is
amount of power, detonation suppression and volatility for
necessary for D7719 fuel.
high performance piston-engine aircraft. The engines and
aircraftimposeavarietyofmechanical,physical,andchemical X2.2.3 Since isopropyl alcohol (IPA) is normally added in
environments.ThepropertiesofD7719fuel(Table1)arefixed thefieldatthepointofsaleasafuelsystemicinginhibitor,the
by this specification in order to give satisfactory engine operatoriscautionedthatitcanimpactoctaneperformanceand
performance over an extremely wide range of conditions for therefore may not meet specification minimums. It has been
aircraft certified to use this fuel. observed that when isopropyl alcohol (IPA) is added to an
aviationgasolineasafuelsystemicinginhibitor,theantiknock
X2.1.2 TheASTM requirements summarized in Table 1 are
rating of the fuel can be reduced.
quality limits established on the basis of Guide D7826
guidelines, which include laboratory testing, engine testing, X2.2.4 Blends with Other Aviation Gasolines—It is antici-
flighttesting,toxicologytesting,materialcompatibilitytesting, pated that D7719 fuel could potentially be mixed with other,
ongoing certification testing, and close cooperation of produc- existingaviationgasolinesinaircraftfueltanks.Testingresults
ers of aviation gasoline, manufacturers of aircraft engines, and for a range of blends of D7719 fuel with 100LL aviation
usersofbothcommodities.ThevaluesgivendefineD7719fuel gasoline is provided in an ASTM research report and shows
intended for use in spark-ignition aviation engines and air- some antagonistic octane blending effects.Additional research
frames certified to use this fuel. may be necessary to evaluate the impact of blending on the
octane rating of the blended fuel relative to the minimum
X2.1.3 This specification includes only one grade of D7719
6,7,8
octane rating of currently available aviation gasolines.
fuel defined by its antiknock quality. The other requirements
prescribe a suite of properties to support production, quality X2.2.5 The composition of D7719 fuel impacts the maxi-
control, and distribution of the
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D7719 − 21 D7719 − 21a An American National Standard
Standard Specification for
High Aromatic Content Unleaded Hydrocarbon Aviation
Gasoline Test Fuel
This standard is issued under the fixed designation D7719; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This specification covers formulating specifications for purchases of a high aromatic content unleaded hydrocarbon aviation
gasoline test fuel under contract and is intended solely for use by purchasing agencies.agencies for testing purposes.
1.2 This specification defines a specific type of high aromatic content unleaded hydrocarbon aviation gasoline (hereafter also
referred to as “D7719 fuel”) for use as an aviation spark-ignition test fuel. It does not include all fuels satisfactory for reciprocating
aviation engines. Certain equipment or conditions of use may permit a wider, or require a narrower, range of characteristics than
is shown by this specification.
1.3 The D7719 fuel defined by this specification does not exhibit identical performance to those leaded fuels for which the existing
aircraft and ground-based fuel handling equipment have been designed to operate on. Therefore, the suitability of this test fuel for
use on any specific aircraft, aircraft engine, or ground-based fuel handling equipment should be evaluated before use on that
equipment.
1.4 Issuance of this specification does not constitute approval to operate certificated aircraft with this fuel. 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 certification program for that aircraft and engine model.
1.5 This specification, unless otherwise provided, prescribes the required properties of unleaded D7719 test fuel at the time and
place of delivery.
1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.8 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
This specification is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.J0.02 on Spark and Compression Ignition Aviation Aviation Piston Engine Fuels.
Current edition approved May 1, 2021July 1, 2021. Published June 2021August 2021. Originally approved in 2011. Last previous edition approved in 20182021 as
D7719 – 18.D7719 – 21. DOI: 10.1520/D7719-21.10.1520/D7719-21A.
Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D02-1721. Contact ASTM Customer
Service at [e-mail].
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7719 − 21a
2. Referenced Documents
2.1 ASTM Standards:
D86 Test Method for Distillation of Petroleum Products and Liquid Fuels at Atmospheric Pressure
D130 Test Method for Corrosiveness to Copper from Petroleum Products by Copper Strip Test
D323 Test Method for Vapor Pressure of Petroleum Products (Reid Method)
D873 Test Method for Oxidation Stability of Aviation Fuels (Potential Residue Method)
D909 Test Method for Supercharge Rating of Spark-Ignition Aviation Gasoline
D910 Specification for Leaded Aviation Gasolines
D1094 Test Method for Water Reaction of Aviation Fuels
D1266 Test Method for Sulfur in Petroleum Products (Lamp Method)
D1298 Test Method for Density, Relative Density, or API Gravity of Crude Petroleum and Liquid Petroleum Products by
Hydrometer Method
D2386 Test Method for Freezing Point of Aviation Fuels
D2622 Test Method for Sulfur in Petroleum Products by Wavelength Dispersive X-ray Fluorescence Spectrometry
D2624 Test Methods for Electrical Conductivity of Aviation and Distillate Fuels
D2700 Test Method for Motor Octane Number of Spark-Ignition Engine Fuel
D3237 Test Method for Lead in Gasoline by Atomic Absorption Spectroscopy
D3606 Test Method for Determination of Benzene and Toluene in Spark Ignition Fuels by Gas Chromatography
D4052 Test Method for Density, Relative Density, and API Gravity of Liquids by Digital Density Meter
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4171 Specification for Fuel System Icing Inhibitors
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products
D4294 Test Method for Sulfur in Petroleum and Petroleum Products by Energy Dispersive X-ray Fluorescence Spectrometry
D4306 Practice for Aviation Fuel Sample Containers for Tests Affected by Trace Contamination
D4809 Test Method for Heat of Combustion of Liquid Hydrocarbon Fuels by Bomb Calorimeter (Precision Method)
D4814 Specification for Automotive Spark-Ignition Engine Fuel
D4865 Guide for Generation and Dissipation of Static Electricity in Petroleum Fuel Systems
D5006 Test Method for Measurement of Fuel System Icing Inhibitors (Ether Type) in Aviation Fuels
D5059 Test Methods for Lead and Manganese in Gasoline by X-Ray Fluorescence Spectroscopy
D5191 Test Method for Vapor Pressure of Petroleum Products and Liquid Fuels (Mini Method)
D5580 Test Method for Determination of Benzene, Toluene, Ethylbenzene, p/m-Xylene, o-Xylene, C and Heavier Aromatics,
and Total Aromatics in Finished Gasoline by Gas Chromatography
D6469 Guide for Microbial Contamination in Fuels and Fuel Systems
D6733 Test Method for Determination of Individual Components in Spark Ignition Engine Fuels by 50-Metre Capillary High
Resolution Gas Chromatography
D7220 Test Method for Sulfur in Automotive, Heating, and Jet Fuels by Monochromatic Energy Dispersive X-ray Fluorescence
Spectrometry
D7826 Guide for Evaluation of New Aviation Gasolines and New Aviation Gasoline Additives
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
3. Terminology
3.1 Definitions:
3.1.1 binary, adj—characterized by, or consisting of, two components.
3.1.2 biomass, n—biological material including any material other than fossil fuels which is or was a living organism or
component or product of a living organism.
3.1.3 non-hydrocarbon, n—compound or compounds composed of carbon, hydrogen, and other elements such as oxygen,
nitrogen, sulfur, and phosphorus.
3.1.4 unleaded hydrocarbon aviation gasoline, n—gasoline intended for use in aircraft powered by reciprocating spark-ignition
engines, where lead and lead-containing compounds are not intentionally added for the purpose of enhancing octane performance
and which excludes non-hydrocarbons, except for additives approved in this specification.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
D7719 − 21a
4. General
4.1 This specification, unless otherwise provided, prescribes the required properties of a high aromatic content unleaded
hydrocarbon aviation gasoline test fuel at the time and place of delivery.
5. Classification
5.1 One grade of high aromatic content unleaded hydrocarbon aviation gasoline is provided, known as UL102.
6. Materials and Manufacture
6.1 D7719 fuel, except as otherwise specified in this specification, shall consist of blends of refined hydrocarbons. The sources
for these hydrocarbons include biomass, natural gas, or crude petroleum.
6.1.1 See Appendix X1 for one particular composition that meets the parameters of Table 1.
A
TABLE 1 Detailed Requirements for High Aromatic Content Unleaded Hydrocarbon Aviation Gasoline Test Fuel
B
Grade UL102 ASTM Test Method
Property
COMBUSTION
Octane Rating min 102.2 D2700
C
Knock value, Motor Octane Number
Net heat of combustion, MJ/kg min 41.5 D4809
COMPOSITION
Sulfur, mass % max 0.05 D1266, D2622, D4294, or D7220
Tetraethyl Lead, g Pb/L max 0.013 D3237 or D5059
Total Aromatics, % (m/m) min 70 D6733
D
Benzene, % (m/m) max 0.1 D3606 or D5580
Requirements for All Grades
VOLATILITY
Vapor pressure, 37.8 °C, kPa min 38.0
E
D323 or D5191
max 49.0
Density at 15 °C, kg/m min 790
D1298 or D4052
max 825
Distillation D86
Initial boiling point, °C Report D86
Fuel Evaporated D86
10 volume % at °C max 75 D86
40 volume % at °C min 75 D86
50 volume % at °C max 165 D86
90 volume % at °C max 165 D86
Final boiling point, °C max 180 D86
Sum of 10 % + 50 % evaporated temperatures, °C min 135 D86
Recovery, volume % min 97 D86
Residue, volume % max 1.5 D86
Loss, volume % max 1.5 D86
FLUIDITY
F
Freezing point, °C max –58 D2386
CORROSION
Copper strip, 2 h at 100 °C max No. 1 D130
CONTAMINANTS
G
Oxidation stability (5 h aging)
D873
Potential gum, mg/100 mL max 6
Water reaction
D1094
Volume change, mL max ±2
OTHER
H
Electrical conductivity, pS/m max 600 D2624
A
For compliance of test results against the requirements of Table 1, see 7.2.
B
The test methods indicated in this table are referred to in Section 11.
C
Knock ratings shall be reported to the nearest 0.1 octane number.
D
In case of dispute, Test Method D3606 shall be used as the referee method.
E
Test Method D5191 shall be the referee vapor pressure method.
F
If no crystals have appeared on cooling to –58 °C, the freezing point may be reported as less than –58 °C.
G
If mutually agreed upon between the purchaser and the supplier, a 16 h aging gum requirement may be specified instead of the 5 h aging gum test; in such case the
gum content shall not exceed 10 mg ⁄100 mL. In such fuel the permissible antioxidant shall not exceed 24 mg ⁄L.
H
Applies only when an electrical conductivity additive is used; when a customer specifies fuel containing conductivity additive, the following conductivity limits shall apply
under the condition at point of use:
Minimum 50 pS ⁄m
Maximum 600 pS ⁄m.
The supplier shall report the amount of additive added.
D7719 − 21a
6.2 Additives—These can be added to each grade of D7719 fuel in the amount, and of the composition, specified in the following
list of approved materials:
6.2.1 Dyes—The total maximum concentration of dye in the fuel is 6.0 mg/L. (See X1.1.1 and X2.2.7.)
6.2.1.1 The only blue dye present in the finished fuel shall be essentially 1,4-dialkylaminoanthraquinone.
6.2.1.2 The only yellow dyes in the finished fuel shall be essentially p-diethylaminoazobenzene (Color Index No. 11021) or
1,3-benzenediol 2,4-bis [(alkylphenyl)azo-].
6.2.1.3 The only red dye present in the finished fuel shall be essentially alkyl derivatives of azobenzene-4-azo-2-naphthol.
6.2.1.4 The only orange dye present in the finished fuel shall be essentially benzene-azo-2-napthol (Color Index No. 12055).
6.2.2 Other Additives—These may be added in the amount and of the composition specified in the following list of approved
materials. The quantities and types shall be declared by the manufacturer. Additives added after the point of manufacture shall also
be declared.
6.2.2.1 Antioxidants—The following oxidation inhibitors may be added to the fuel separately, or in combination, in total
concentration not to exceed 12 mg of inhibitor (not including weight of solvent) per litre of fuel.
(1) 2,6-ditertiary butyl-4-methylphenol.
(2) 2,4-dimethyl-6-tertiary butylphenol.
(3) 2,6-ditertiary butylphenol.
(4) 75 % minimum 2,6-ditertiary butylphenol plus 25 % maximum mixed tertiary and tritertiary butylphenols.
(5) 75 % minimum di- and tri-isopropyl phenols plus 25 % maximum di- and tri-tertiary butylphenols.
(6) 72 % minimum 2,4-dimethyl-6-tertiary butylphenol plus 28 % maximum monomethyl and dimethyl tertiary butylphenols.
(7) N,N’-di-isopropyl-para-phenylenediamine.
(8) N,N’-di-secondary-butyl-para-phenylenediamine.
D7719 − 21a
6.2.2.2 Fuel System Icing Inhibitor (FSII)—One of the following materials may be used:
(1) Isopropyl Alcohol (IPA, propan-2-ol), in accordance with the requirements of Specification D4171 (Type II). May be used
in concentrations recommended by the aircraft manufacturer when required by the aircraft owner/operator.
(2) Di-Ethylene Glycol Monomethyl Ether (Di-EGME), conforming to the requirements of Specification D4171 (Type III).
May be used in concentrations of 0.10 % to 0.15 % by volume when required by the aircraft owner/operator.
(3) Test Method D5006 can be used to determine the concentration of Di-EGME in aviation fuels.
NOTE 1—Addition of isopropyl alcohol (IPA) may reduce knock ratings below minimum specification values. See X2.2.3.
6.2.2.3 Electrical Conductivity Additive—Stadis® 450 in concentrations up to 3 mg/L is permitted. When loss of fuel conductivity
necessitates retreatment with electrical conductivity additive, further addition is permissible up to a maximum cumulative level of
5 mg ⁄L of Stadis® 450.
6.2.2.4 Corrosion Inhibitor Additive—The following corrosion inhibitors may be added to the fuel in concentrations not to exceed
the maximum allowable concentration (MAC) listed for each additive.
DCI-4A MAC = 24.0 g/m
DCI-6A MAC = 15.0 g/m
HITEC 580 MAC = 22.5 g/m
NALCO 5403 MAC = 22.5 g/m
NALCO 5405 MAC = 11.0 g/m
UNICOR J MAC = 22.5 g/m
SPEC-AID 8Q22 MAC = 24.0 g/m
TOLAD 351 MAC = 24.0 g/m
TOLAD 4410 MAC = 22.5 g/m
7. Detailed Requirements
7.1 The D7719 fuel shall conform to the requirements prescribed in Table 1.
7.2 Test results shall not exceed the maximum or be less than the minimum values specified in Table 1. No allowance shall be
made for the precision of the test methods. To determine the conformance to the specification requirement, a test result may be
rounded to the same number of significant figures as in Table 1 using Practice E29. Where multiple determinations are made, the
average result, rounded according to Practice E29, shall be used.
8. Workmanship, Finish, and Appearance
8.1 The D7719 fuel specified in this specification shall be free from undissolved water, sediment, and suspended matter. No
substances of known dangerous toxicity, under usual conditions of handling and use, shall be present except as permitted in this
specification.
9. Sampling
9.1 Because of the importance of proper sampling procedures in establishing fuel quality, use the appropriate procedures in
Practice D4057 or Practice D4177.
9.1.1 Although automatic sampling following Practice D4177 may be useful in certain situations, initial manufacturer/supplier
specification compliance testing shall be performed on a sample taken following procedures in Practice D4057.
9.2 A number of D7719 fuel properties, including copper corrosion, electrical conductivity, and others are very sensitive to trace
contamination which can originate from sample containers. For recommended sample containers, refer to Practice D4306.
10. Reports
10.1 The type and number of reports to ensure conformance with the requirements of this specification shall be mutually agreed
to by the purchaser and the supplier of the D7719 fuel.
Stadis® 450 is a registered trademark marketed by Innospec, Inc., Innospec Manufacturing Park, Oil Sites Road, Ellesmere Port, Cheshire, CH65 4EY, UK.
D7719 − 21a
11. Test Methods
11.1 The requirements enumerated in this specification shall be determined in accordance with the following ASTM test methods:
11.1.1 Knock Value (Motor Octane Number)—Test Method D2700.
11.1.2 Tetraethyl Lead—Test Methods D3237 or D5059.
11.1.3 Density—Test Methods D1298 or D4052.
11.1.4 Distillation—Test Method D86.
11.1.5 Freezing Point—Test Method D2386.
11.1.6 Vapor Pressure—Test Methods D323 or D5191.
11.1.7 Net Heat of Combustion—Test Method D4809.
11.1.8 Sulfur—Test Methods D1266, D2622, D4294, or D7220.
11.1.9 Corrosion (Copper Strip)—Test Method D130, 2 h test at 100 °C in bomb.
11.1.10 Potential Gum and Visible Lead Precipitate—Test Method D873 except that wherever the letter X occurs (referring to
oxidation time) insert the number 5, designating the number of hours prescribed in this specification.
11.1.11 Water Reaction—Test Method D1094.
11.1.12 Electrical Conductivity—Test Method D2624.
11.1.13 Aromatic Content—Test Method D6733.
11.1.14 Benzene Content—Test Methods D3606 or D5580.
12. Keywords
12.1 aviation gasoline; binary; hydrocarbon; unleaded
APPENDIXES
(Nonmandatory Information)
X1. HIGH AROMATIC CONTENT BINARY UNLEADED HYDROCARBON AVIATION GASOLINE COMPOSITION
X1.1 Introduction
X1.1.1 A new high aromatic content unleaded hydrocarbon aviation gasoline has been developed for reciprocating aircraft
engines. The two essential performance parameters of MON and VP are inversely related with respect to composition and thus can
uniquely define a composition range of the two components. The values for VP and MON in Table 1 reflect the limiting values
of the two components. The distillation parameters reflect the binary compositional effects. This is an unleaded fuel, so the limit
of TEL in Table 1 is the same as is used in Specification D4814 for mogas and is meant to mitigate unintentional contamination
by TEL. Lastly, references to dyes remain in the specification so that test groups may use them as necessary. This specification
covers a high-octane unleaded hydrocarbon aviation gasoline developed for existing spark-ignition aircraft engines.
Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D02-1808. Contact ASTM Customer
Service at [e-mail].
D7719 − 21a
X1.2 Composition
X1.2.1 The origin of the fuel lies in two essential engine performance parameters: Motor Octane Number, and Vapor Pressure. Fig.
X1.1 shows the inverse relationship of these two parameters as a function of mesitylene composition.
X1.2.2 These two parameters coupled with the fact that the fuel is a binary composition, fix the effective composition range as
follows:
(1) High-Octane Composition: 84 % mesitylene 16 % isopentane
(2) High Limit Reid Composition 79 % mesitylene 21 % isopentane
X1.2.3 These limits are proposed to define the binary fuel’s specification composition.
FIG. X1.1 Motor Octane Number and Vapor Pressure versus % Mesitylene
D7719 − 21a
X2. PERFORMANCE CHARACTERISTICS OF HIGH AROMATIC CONTENT UNLEADED HYDROCARBON AVIATION
GASOLINE
X2.1 Introduction
X2.1.1 High aromatic content unleaded hydrocarbon aviation gasoline (hereafter referred to as “D7719 fuel”) is a mixture of
hydrocarbons that result in a narrow range of physical and chemical properties to assure an appropriate amount of power,
detonation suppression and volatility for high performance piston-engine aircraft. The engines and aircraft impose a variety of
mechanical, physical, and chemical environments. The properties of D7719 fuel (Table 1) are fixed by this specification in order
to give satisfactory engine performance over an extremely wide range of conditions for aircraft certified to use this fuel.
X2.1.2 The ASTM requirements summarized in Table 1 are quality limits established on the basis of Guide D7826 guidelines,
which include laboratory testing, engine testing, flight testing, toxicology testing, material compatibility testing, ongoing
certification testing, and close cooperation of producers of aviation gasoline, manufacturers of aircraft engines, and users of both
commodities. The values given define D7719 fuel intended for use in spark-ignition aviation engines and airframes certified to use
this fuel.
X2.1.3 This specification includes only one grade of D7719 fuel defined by its antiknock quality. The other requirements prescribe
a suite of properties to support production, quality control, and distribution of the fuel.
X2.2 Combustion Characteristics and Antiknock Quality
X2.2.1 The fuel-air mixture in the cylinder of a spark-ignition engine will, under certain conditions, ignite spontaneously in
localized areas instead of progressing from the spark. This can cause a detonation or knock, usually inaudible in aircraft engines.
This knock, if permitted to continue for more than brief periods, can result in serious loss of power and damage to, or destruction
of, the aircraft engine. Should D7719 fuel be used in other types of aviation engines, for example, in certain turbine engines where
specifically approved by the engine manufacturers, knock or detonation characteristics may not be critical requirements.
Modifications or adjustments to avoid knock or detonation when operating with D7719 fuel on aircraft engines originally designed
to operate on other aviation gasolines should consider the impacts that those modifications or adjustments can have on aircraft or
engine performance.
X2.2.2 The D7719 fuel grade is rated based upon an ASTM Motor Octane Number (MON) which expressed a knock value based
upon a standard laboratory test (Test Method D2700). The MON is a measure of how the fuel behaves when under load (stress).
MON testin
...