ASTM F3331-18

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Designation: F3331 − 18
Standard Practice for
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Aircraft Water Loads
This standard is issued under the fixed designation F3331; 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 2. Referenced Documents
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1.1 This practice provides equations for calculating water 2.1 ASTM Standards:
loads for aeroplane dual floats and single hulls. The material F3060 Terminology for Aircraft
was developed through open consensus of international experts
3. Terminology
in general aviation. This information was created by focusing
on Level 1, 2, 3, and 4 Normal Category aeroplanes. The 3.1 A listing of terms, abbreviations, acronyms, and sym-
content may be more broadly applicable; it is the responsibility bols related to aircraft covered by ASTM Committees F37 and
of the Applicant to substantiate broader applicability as a F44 airworthiness design standards can be found in Terminol-
specific means of compliance. ogy for Aircraft F3060. Items listed below are more specific to
this standard.
1.2 An applicant intended to propose this information as
Means of Compliance for a design approval must seek guid-
4. Significance and Use
ance from their respective oversight authority (for example,
4.1 This practice provides one means for determining the
published guidance from applicable CAAs) concerning the
aeroplane structural loads for either dual floats or single hulls
acceptable use and application thereof. For information on
when taxiing on, taking off from, or landing on water. This
which oversight authorities have accepted this standard (in
practice satisfies the water loads requirements set forth in the
whole or in part) as an acceptable Means of Compliance to
Design Loads and Conditions Specification for Normal Cat-
their regulatory requirements (hereinafter “the Rules”), refer to
egory Aeroplanes.
ASTM Committee F44 web page (www.astm.org/
COMMITTEE/F44.htm).
5. Calculation of Aeroplane Water Loads
1.3 Units—The values stated in inch-pound units are to be
5.1 Design Weights and Center of Gravity Positions:
regarded as standard.
5.1.1 Design Weights—The water load requirements must
1.4 This standard does not purport to address all of the be met at each operating weight up to the design landing
safety concerns, if any, associated with its use. It is the weight except that, for the takeoff condition prescribed in 5.5,
responsibility of the user of this standard to establish appro- the design water takeoff weight (the maximum weight for
water taxi and takeoff run) must be used.
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use. 5.1.2 Center of Gravity—The critical centers of gravity
within the limits for which certification is requested must be
1.5 This international standard was developed in accor-
dance with internationally recognized principles on standard- considered to reach maximum design loads for each part of the
seaplane structure.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
5.2 Application of Loads:
mendations issued by the World Trade Organization Technical
5.2.1 Unless otherwise prescribed, the seaplane as a whole
Barriers to Trade (TBT) Committee.
is assumed to be subjected to the loads corresponding to the
load factors specified in 5.3.
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This practice is under the jurisdiction of ASTM Committee F44 on General
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Aviation Aircraft and is the direct responsibility of Subcommittee F44.30 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Structures. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Current edition approved Sept. 1, 2018. Published October 2018. DOI: 10.1520/ Standards volume information, refer to the standard’s Document Summary page on
F3331-18. the ASTM website.
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F3331 − 18
5.2.2 In applying the loads resulting from the load factors
prescribed in 5.3, the loads may be distributed over the hull or
main float bottom (in order to avoid excessive local shear loads
and bending moments at the location of water load application)
using pressures not less than those prescribed in 5.6.3.
5.2.3 For twin float seaplanes, each float must be treated as
an equivalent hull on a fictitious seaplane with a weight equal
to one-half the weight of the twin float seaplane.
5.2.4 Except in the takeoff condition of 5.5, the aerody-
namic lift on t
...