ASTM_F_3331_-_18.pdf

Designation:F333118Standard Practice forAircraft Water Loads1This standard is issued under the fixed designation F3331;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice provides equations for calculating waterloads for aeroplane dual floats and single hulls.The materialwas developed through open consensus of international expertsin general aviation.This information was created by focusingon Level 1,2,3,and 4 Normal Category aeroplanes.Thecontent may be more broadly applicable;it is the responsibilityof the Applicant to substantiate broader applicability as aspecific means of compliance.1.2 An applicant intended to propose this information asMeans of Compliance for a design approval must seek guid-ance from their respective oversight authority(for example,published guidance from applicable CAAs)concerning theacceptable use and application thereof.For information onwhich oversight authorities have accepted this standard(inwhole or in part)as an acceptable Means of Compliance totheir regulatory requirements(hereinafter“the Rules”),refer toASTMCommitteeF44webpage(www.astm.org/COMMITTEE/F44.htm).1.3 UnitsThe values stated in inch-pound units are to beregarded as standard.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2F3060 Terminology for Aircraft3.Terminology3.1 A listing of terms,abbreviations,acronyms,and sym-bols related to aircraft covered by ASTM Committees F37 andF44 airworthiness design standards can be found in Terminol-ogy for Aircraft F3060.Items listed below are more specific tothis standard.4.Significance and Use4.1 This practice provides one means for determining theaeroplane structural loads for either dual floats or single hullswhen taxiing on,taking off from,or landing on water.Thispractice satisfies the water loads requirements set forth in theDesign Loads and Conditions Specification for Normal Cat-egory Aeroplanes.5.Calculation of Aeroplane Water Loads5.1 Design Weights and Center of Gravity Positions:5.1.1 Design WeightsThe water load requirements mustbe met at each operating weight up to the design landingweight except that,for the takeoff condition prescribed in 5.5,the design water takeoff weight(the maximum weight forwater taxi and takeoff run)must be used.5.1.2 Center of GravityThe critical centers of gravitywithin the limits for which certification is requested must beconsidered to reach maximum design loads for each part of theseaplane structure.5.2 Application of Loads:5.2.1 Unless otherwise prescribed,the seaplane as a wholeis assumed to be subjected to the loads corresponding to theload factors specified in 5.3.1This practice is under the jurisdiction of ASTM Committee F44 on GeneralAviation Aircraft and is the direct responsibility of Subcommittee F44.30 onStructures.Current edition approved Sept.1,2018.Published October 2018.DOI:10.1520/F3331-18.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 5.2.2 In applying the loads resulting from the load factorsprescribed in 5.3,the loads may be distributed over the hull ormain float bottom(in order to avoid excessive local shear loadsand 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 asan equivalent hull on a fictitious seaplane with a weight equalto 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 the seaplane during the impact is assumed to be23of the weight of the seaplane.5.3 Water Load