ASTM F2339-19a

Standard Practice for Design and Manufacture of Reciprocating Spark Ignition Engines for Light Sport Aircraft

SIGNIFICANCE AND USE
3.1 This practice provides designers and manufacturers of engines for light sport aircraft design references and criteria to use in designing and manufacturing engines.  
3.2 Declaration of compliance is based on testing and documentation during the design and testing or flight testing of the engine type by the manufacturer or under the manufacturers' guidance.
SCOPE
1.1 This practice covers minimum requirements for the design and manufacture of reciprocating spark ignition engines for light sport aircraft, VFR use.  
1.2 The values stated in inch-pound units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 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.  
1.4 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: 31-Oct-2019
• ICS: 49.060 - Aerospace electric equipment and systems
• Technical Committee: F37 - Light Sport Aircraft
• Drafting Committee: F37.70 - Cross Cutting

Relations

• Replaces: ASTM F2339-19 - Standard Practice for Design and Manufacture of Reciprocating Spark Ignition Engines for Light Sport Aircraft
• Effective Date: 01-Nov-2019
• Referred By: ASTM F2317/F2317M-16a - Standard Specification for Design of Weight-Shift-Control Aircraft
• Effective Date: 01-Nov-2019
• Referred By: ASTM F2352-14(2022) - Standard Specification for Design and Performance of Light Sport Gyroplane Aircraft
• Effective Date: 01-Nov-2019
• Referred By: ASTM F2245-23 - Standard Specification for Design and Performance of a Light Sport Airplane
• Effective Date: 01-Nov-2019
• Referred By: ASTM F2564-14(2022) - Standard Specification for Design and Performance of a Light Sport Glider
• Effective Date: 01-Nov-2019
• Referred By: ASTM F2506-22 - Standard Specification for Design and Testing of Light Sport Aircraft Propellers
• Effective Date: 01-Nov-2019
• Referred By: ASTM F3062/F3062M-20 - Standard Specification for Aircraft Powerplant Installation
• Effective Date: 01-Nov-2019

Overview

ASTM F2339-19a is the international standard practice developed by ASTM International for the design and manufacture of reciprocating spark ignition engines specifically intended for light sport aircraft (LSA) operating under Visual Flight Rules (VFR). This standard sets out the essential minimum requirements, references, criteria, and testing protocols that designers and manufacturers must follow to ensure engines are fit for safe, reliable flight operations in sport aviation.

The guidance in ASTM F2339-19a is designed to support the declaration of compliance by engine manufacturers, which is based on comprehensive documentation and testing conducted during the development, qualification, and flight verification phases. The standard is recognized globally and prepared in adherence to principles established by the WTO Technical Barriers to Trade (TBT) Committee, ensuring broad industry acceptance and alignment with international best practices.

Key Topics

• Minimum Design and Performance Criteria
  • Outlines baseline materials, fire prevention, engine cooling, mounting, ignition, lubrication, vibration, and system requirements.
• Documentation and Recordkeeping
  • Details required retained data (design drawings, specifications, analyses, and test data) to be archived for at least 18 years post-production.
  • Lists crucial operational documentation to be delivered with the engine, including installation, operation, maintenance, and overhaul manuals.
• Testing and Compliance
  • Specifies qualification testing such as calibration, detonation, and durability (using accelerated overhaul or fleet leader methods).
  • Details requirements for system reliability, especially for Electronic Engine Controllers (EEC).
• Manufacturing Controls
  • Emphasizes robust inspection protocols for materials, production, assembly, and nonconforming parts management.
• Safety and Regulatory Considerations
  • Provides guidance for risk assessment, compliance with applicable health, safety, and environmental regulations, and adaptability to varying global regulatory frameworks.

Applications

ASTM F2339-19a is vital for stakeholders in the light sport aircraft industry, including:

• Engine Designers and Manufacturers
  • Provides a clear framework for developing reciprocating spark ignition engines compliant with LSA requirements.
• Aircraft OEMs
  • Facilitates the integration and certification of engines into light sport airframes, ensuring installation meets defined interface and operational limits.
• Maintenance and Overhaul Providers
  • Supplies structured guidelines for periodic maintenance and major inspections, contributing to long-term airworthiness and safety.
• Aviation Authorities and Auditors
  • Supports regulatory review, compliance checks, and acceptance of LSA engine products based on a recognized international standard.
• Aviation Operators and Pilots
  • Ensures that aircraft engines deliver consistent, reliable performance and come with comprehensive documentation for safe use and ongoing support.

By adhering to ASTM F2339-19a, the sport aviation industry can ensure engines are consistently manufactured and documented to high-quality, safety-focused standards, supporting international acceptance and reducing barriers to trade.

Related Standards

Several referenced documents and related standards are instrumental when applying ASTM F2339-19a:

• ASTM F3153 - Specification for Verification of Avionics Systems
  • Relevant for verifying electronic engine control systems and environmental qualification.
• RTCA DO-178 - Software Considerations in Airborne Systems and Equipment Certification
  • Guides software development, verification, and compliance for EECs.
• RTCA DO-254 - Design Assurance Guidance for Airborne Electronic Hardware
  • Provides direction for certifying hardware used in aviation engines.
• FAA AC 33.28
  • Offers additional guidance material for engine control systems compliance.

By referencing these related standards, manufacturers and integrators can address both design quality and rigorous technical verification, supporting robust and compliant LSA engine products.

Keywords: light sport aircraft engine, reciprocating spark ignition engine, ASTM F2339-19a, engine compliance, aviation engine standards, engine testing, engine manufacturing, LSA engine documentation

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: F2339 − 19a
Standard Practice for
Design and Manufacture of Reciprocating Spark Ignition
Engines for Light Sport Aircraft
This standard is issued under the fixed designation F2339; 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 3.2 Declaration of compliance is based on testing and
documentation during the design and testing or flight testing of
1.1 This practice covers minimum requirements for the
the engine type by the manufacturer or under the manufactur-
design and manufacture of reciprocating spark ignition engines
ers’ guidance.
for light sport aircraft, VFR use.
1.2 The values stated in inch-pound units are to be regarded
4. Engine Model Designation
as standard. No other units of measurement are included in this
4.1 Engine Parts List—A parts list is required for each
standard.
engine model qualified in accordance with this specification.
1.3 This standard does not purport to address all of the
4.2 New Engine Model Designations:
safety concerns, if any, associated with its use. It is the
4.2.1 Each new engine model must be qualified in accor-
responsibility of the user of this standard to establish appro-
dance with this practice.
priate safety, health, and environmental practices and deter-
4.2.2 Design or configuration changes that impact the in-
mine the applicability of regulatory limitations prior to use.
stallation interface, performance, or operability of the engine
1.4 This international standard was developed in accor-
require a new engine model designation.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
4.3 Design Changes of Parts—Each design change of a part
Development of International Standards, Guides and Recom- or component of an engine model qualified to this specification
mendations issued by the World Trade Organization Technical
should be evaluated relative to the requirements of this
Barriers to Trade (TBT) Committee. specification.
2. Referenced Documents
5. Data Requirements
2.1 ASTM Standard: 5.1 Retained Data—The following data and information
F3153 Specification for Verification of Avionics Systems should be retained on file at the manufacturer’s facility for at a
2 minimum of 18 years after production is discontinued.
2.2 RTCA Standards:
5.1.1 Drawings that define the engine configuration.
DO-178 Software Considerations in Airborne Systems and
5.1.2 Material and process specifications referenced in the
Equipment Certification
parts drawings.
DO-254 DesignAssuranceGuidanceforAirborneElectronic
5.1.3 Engineering analyses and test data prepared for quali-
Hardware
fication with this specification.
3. Significance and Use
5.2 Delivered Data—The following data should be deliv-
ered to the airplane manufacturer to support design and
3.1 This practice provides designers and manufacturers of
operation of the applicable airplane.
engines for light sport aircraft design references and criteria to
5.2.1 An engine performance specification that defines the
use in designing and manufacturing engines.
engine performance under all anticipated operating environ-
ments.
5.2.2 An installation manual that defines all functional and
This practice is under the jurisdiction ofASTM Committee F37 on Light Sport
physical interface requirements of the engine. This should
Aircraft and is the direct responsibility of Subcommittee F37.70 on Cross Cutting.
Current edition approved Nov. 1, 2019. Published March 2020. Originally
include an engine outline/installation drawing.
approved in 2004. Last previous edition approved in 2019 as F2339–19. DOI:
5.2.3 An operating manual that defines normal and abnor-
10.1520/F2339–19A.
mal operating procedures and any applicable operating limita-
Available from RTCA, 1150 18th NW, Suite 910, Washington, DC 20036,
https://www.rtca.org. tions.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F2339 − 19a
5.2.4 A maintenance manual that defines periodic installed 6.7 Fuel and Induction System:
maintenance, major inspection, overhaul intervals, and any 6.7.1 Induction System Icing—The fuel and air intake pas-
other maintenance limitations. sages must be designed to minimize the accretion of ice.
5.2.5 An overhaul manual that provides instruction for 6.7.2 Filtering—Thetypeanddegreeoffuelandairfiltering
necessary to prevent obstruction of air or fuel flow must be
disassembling the engine to replace or repair, or both, parts as
required to return the engine to airworthy condition that is safe specified.
6.7.3 Liquid Lock—Each passage in the induction system
for operation until the next major overhaul.
that conducts a mixture of fuel and air must be self-draining or
demonstrated to not cause damage from hydraulic lock on
6. Design Criteria
starting.
6.1 Materials—The materials used in the engine must be
6.8 Lubrication System:
adequate for the intended design conditions of the engine.
6.8.1 The lubrication system of the engine must be designed
6.2 Fire Prevention—The design and construction of the
and constructed so that it will function properly in all flight
engine and the materials used must minimize the probability of
attitudes and atmospheric conditions in which the engine is
the occurrence and spread of fire by:
expected to operate. In wet sump engines, this requirement
6.2.1 Using fire-resistant lines, fittings, and other compo-
must be met when only one-half of the maximum lubricant
nents that contain a flammable liquid when supplied with the
supply is in the engine.
engine; and
6.8.2 The lubrication system of the engine must be designed
6.2.2 Shielding or locating components to safeguard against
and constructed to allow installing a means of cooling the
the ignition of leaking flammable fluid.
lubricant if required.
6.3 Engine Cooling—The engine design must include pro- 6.8.3 The crankcase on four-stroke engines must be vented
visionsforcooling;theinstallationmanualmustspecifyengine to the atmosphere to preclude leakage of oil from excessive
and component temperature limitations. pressure in the crankcase. This venting must have a means to
prevent the blockage of the vent by ice.
6.4 Engine Mounting—Attach points on the engine must
have data for the correct design of mounting structures to the 6.9 Vibration General—The engine must be designed and
constructed to function throughout its normal operating range
airframe. The maximum allowable limit and ultimate loads for
the engine mounting attachments and related structure must be of crankshaft rotational speeds and engine powers without
inducing excessive stress in any of the engine parts.
specified.
6.9.1 The engine must have a crankshaft vibration survey to
6.5 IgnitionSystems—Each spark ignition engine must have
determinetorsionalandbendingcharacteristicsfromidlespeed
a dual-ignition system with at least two spark plugs for each
up to maximum desired takeoff speed. This survey should be
cylinderandtwoseparateelectriccircuitswithseparatesources
done with a representative propeller and no hazardous condi-
of electrical energy, or have an ignition system of equivalent
tions would be allowed.
in-flight reliability. System maintenance must be specified
under the maintenance manual supplied by the manufacturer.
7. Qualification Tests
6.5.1 Engines used in aircraft where the engine is not
7.1 Calibration Test—Each engine design shall be tested
required for flight, for example, gliders, can be single ignition.
and the characteristics of engine rated power, speeds, and fuel
6.5.2 Engines for use in only single seat aircraft may use
consumption shall be determined
...

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: F2339 − 19 F2339 − 19a
Standard Practice for
Design and Manufacture of Reciprocating Spark Ignition
Engines for Light Sport Aircraft
This standard is issued under the fixed designation F2339; 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 practice covers minimum requirements for the design and manufacture of reciprocating spark ignition engines for light
sport aircraft, VFR use.
1.2 The values stated in inch-pound units are to be regarded as standard. No other units of measurement are included in this
standard.
1.3 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.
1.4 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.
2. Referenced Documents
2.1 ASTM Standard:
F3153 Specification for Verification of Avionics Systems
2.2 RTCA Standards:
DO-178 Software Considerations in Airborne Systems and Equipment Certification
DO-254 Design Assurance Guidance for Airborne Electronic Hardware
3. Significance and Use
3.1 This practice provides designers and manufacturers of engines for light sport aircraft design references and criteria to use
in designing and manufacturing engines.
3.2 Declaration of compliance is based on testing and documentation during the design and testing or flight testing of the engine
type by the manufacturer or under the manufacturers’ guidance.
4. Engine Model Designation
4.1 Engine Parts List—A parts list is required for each engine model qualified in accordance with this specification.
4.2 New Engine Model Designations:
4.2.1 Each new engine model must be qualified in accordance with this practice.
4.2.2 Design or configuration changes that impact the installation interface, performance, or operability of the engine require
a new engine model designation.
4.3 Design Changes of Parts—Each design change of a part or component of an engine model qualified to this specification
should be evaluated relative to the requirements of this specification.
5. Data Requirements
5.1 Retained Data—The following data and information should be retained on file at the manufacturer’s facility for at a
minimum of 18 years after production is discontinued.
This practice is under the jurisdiction of ASTM Committee F37 on Light Sport Aircraft and is the direct responsibility of Subcommittee F37.70 on Cross Cutting.
Current edition approved April 1, 2019Nov. 1, 2019. Published May 2019March 2020. Originally approved in 2004. Last previous edition approved in 20172019 as
F2339–17.–19. DOI: 10.1520/F2339–19.10.1520/F2339–19A.
Available from RTCA, 1150 18th NW, Suite 910, Washington, DC 20036, https://www.rtca.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F2339 − 19a
5.1.1 Drawings that define the engine configuration.
5.1.2 Material and process specifications referenced in the parts drawings.
5.1.3 Engineering analyses and test data prepared for qualification with this specification.
5.2 Delivered Data—The following data should be delivered to the airplane manufacturer to support design and operation of
the applicable airplane.
5.2.1 An engine performance specification that defines the engine performance under all anticipated operating environments.
5.2.2 An installation manual that defines all functional and physical interface requirements of the engine. This should include
an engine outline/installation drawing.
5.2.3 An operating manual that defines normal and abnormal operating procedures and any applicable operating limitations.
5.2.4 A maintenance manual that defines periodic installed maintenance, major inspection, overhaul intervals, and any other
maintenance limitations.
5.2.5 An overhaul manual that provides instruction for disassembling the engine to replace or repair, or both, parts as required
to return the engine to airworthy condition that is safe for operation until the next major overhaul.
6. Design Criteria
6.1 Materials—The materials used in the engine must be adequate for the intended design conditions of the engine.
6.2 Fire Prevention—The design and construction of the engine and the materials used must minimize the probability of the
occurrence and spread of fire by:
6.2.1 Using fire-resistant lines, fittings, and other components that contain a flammable liquid when supplied with the engine;
and
6.2.2 Shielding or locating components to safeguard against the ignition of leaking flammable fluid.
6.3 Engine Cooling—The engine design must include provisions for cooling; the installation manual must specify engine and
component temperature limitations.
6.4 Engine Mounting—Attach points on the engine must have data for the correct design of mounting structures to the airframe.
The maximum allowable limit and ultimate loads for the engine mounting attachments and related structure must be specified.
6.5 Ignition Systems—Each spark ignition engine must have a dual-ignition system with at least two spark plugs for each
cylinder and two separate electric circuits with separate sources of electrical energy, or have an ignition system of equivalent
in-flight reliability. System maintenance must be specified under the maintenance manual supplied by the manufacturer.
6.5.1 Engines used in aircraft where the engine is not required for flight, for example, gliders, can be single ignition.
6.5.2 Engines for use in only single seat aircraft may use single ignition.
6.6 Electronic Engine Controllers (EEC):
6.6.1 The EEC system must be designed to accommodate single-point failures without significant power reduction.
6.6.2 The functioning of EECs must not be adversely affected by the declared environmental conditions of operation by the
manufacturer, including temperature and moisture. The EEC system, inclusive of hardware and software, must be tested to ensure
that it safely performs its intended functions, in its specified environments for at least the Engine Overhaul Interval (see 7.4). An
acceptableSee Appendix X1 method for showing compliance is the use of ASTM for study materials F3153, Standard Specification
for Verification of Avionics Systems, with the intended functions and test scenarios defined, at minimum, to match specified engine
performance and approved operating environments.and example of acceptable methods of compliance.
6.6.3 The harnesses or cables in the EEC system must be shielded between components and electrically bonded to a common
ground.
6.6.4 The documentation and verification results shall be available for review by the relevant CAA, as required.
6.6.5 The data delivered with the engine (see 5.2) must include appropriate operating limitations and instructions that reflect the
limits to which the system has been qualified.
6.7 Fuel and Induction System:
6.7.1 Induction System Icing—The fuel and air intake passages must be designed to minimize the accretion of ice.
6.7.2 Filtering—The type and degree of fuel and air filtering necessary to prevent obstruction of air or fuel flow must be
specified.
6.7.3 Liquid Lock—Each passage in the induction system that conducts a mixture of fuel and air must be self-draining or
demonstrated to not cause damage from hydraulic lock on starting.
6.8 Lubrication System:
6.8.1 The lubrication system of the engine must be designed and constructed so that it will function properly in all flight
attitudes and a
...