ASTM F3409-19e1
(Practice)Standard Practice for Simplified Aircraft Loads Determination
Standard Practice for Simplified Aircraft Loads Determination
SCOPE
1.1 This practice provides an acceptable, and simplified, means of determining certain design loads criteria and conditions for fixed wing aircraft. In particular, the practice provides overall aircraft flight loads and flight conditions as well as control surface loads, wing loads, gust load factors, and gust loads on stabilizing surfaces.
1.2 This practice is intended to be referenced by other standards that define requirements for comprehensive aircraft loads. This practice does not provide all aircraft loads required for structural compliance. In addition, each load or condition determined through this practice has limitations on its use within the relevant section to which it must adhere.
1.3 Units—The values given in this standard are in SI units and are to be regarded as standard. Any values given in parentheses are mathematical conversions to inch-pound (or other) units that are provided for information only and are not considered standard. The values stated in each system may not be exact equivalents. Where it may not be clear, some equations provide the units of the result directly following the equation.
1.4 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.
1.5 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
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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.
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Designation:F3409 −19
Standard Practice for
1
Simplified Aircraft Loads Determination
This standard is issued under the fixed designation F3409; 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
ε NOTE—The images in Figs. 1 and 2 were interchanged editorially in October 2022.
1. Scope 2. Referenced Documents
2
1.1 This practice provides an acceptable, and simplified, 2.1 ASTM Standards:
means of determining certain design loads criteria and condi- F2245 Specification for Design and Performance of a Light
tions for fixed wing aircraft. In particular, the practice provides Sport Airplane
F3060 Terminology for Aircraft
overall aircraft flight loads and flight conditions as well as
control surface loads, wing loads, gust load factors, and gust F3116/F3116M Specification for Design Loads and Condi-
tions
loads on stabilizing surfaces.
1.2 This practice is intended to be referenced by other
3. Terminology
standards that define requirements for comprehensive aircraft
3.1 Definitions:
loads. This practice does not provide all aircraft loads required
3.1.1 A listing of terms, abbreviations, acronyms, and sym-
for structural compliance. In addition, each load or condition
bols related to aircraft can be found in Terminology F3060.
determined through this practice has limitations on its use
Items listed in 3.2 are more specific to this standard.
within the relevant section to which it must adhere.
3.2 Abbreviations:
1.3 Units—The values given in this standard are in SI units
n = airplane positive maneuvering limit load factor
and are to be regarded as standard. Any values given in 1
n = airplane negative maneuvering limit load factor
parentheses are mathematical conversions to inch-pound (or 2
n = airplane positive gust limit load factor at V
3 C
other) units that are provided for information only and are not
n = airplane negative gust limit load factor at V
4 C
considered standard. The values stated in each system may not
n = airplane positive limit load factor with flaps fully
flap
be exact equivalents. Where it may not be clear, some
extended at V
F
equations provide the units of the result directly following the
V = minimum design flap speed =
Fmin
equation.
0.818 5 =n W ⁄ S
~ !
1.4 This standard does not purport to address all of the 1
safety concerns, if any, associated with its use. It is the
V = design maneuvering speed =
A
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
W
V =n □where□V 5
mine the applicability of regulatory limitations prior to use. S 1 S
1
S D
ρ C S
1.5 This international standard was developed in accor- ! S D
Lmax
2
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
V = minimum design cruising speed
Cmin
Development of International Standards, Guides and Recom-
1.27 5 =n ~W ⁄ S!
1
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
but need not exceed 0.9 V
H
1 2
This practice is under the jurisdiction ofASTM Committee F37 on Light Sport For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Aircraft and is the direct responsibility of Subcommittee F37.20 on Airplane. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Current edition approved Nov. 1, 2019. Published March 2020. DOI: 10.1520/ Standards volume information, refer to the standard’s Document Summary page on
F3409-19E01. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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F3409−19
and n , corresponding to the maximum design weights.
V = minimum design dive speed
4
Dmin
4.2.2 Each flight load may be considered independent of
1.79 5 =n ~W ⁄ S!
1
altitude and, except for the local supporting structure for dead
weight items, only the maximum design weight conditions
but need not exceed
must be investigated.
1.4□V =n ⁄3.8
Cmin 1 4.2.3 Figs. 1 and 2 must be used to determine values of n
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See 4.2.5.2.
and n , corresponding to the minimum flying weights, and if
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V = design cruising speed (if greater than V )
Csel Cmin
these load factors are greater than the load factors at the design
weight, the supporting structure for dead weight items must be
4. Simplified Design Load Criteria
substantiated for the resulting highe
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