(2)
Floats deployed after initial water contact.Each .oatmustbedesignedforfull orpartialimmersionprescribedinparagraph(b)(1) ofthis section.In addition, each .oat must be designed for combined vertical and drag loads using a relative limit speed of 20 knots between the rotorcraft and the water. The verticalload may notbeless than thehighestlikelybuoyancyloaddetermined underparagraph(b)(1) of this section.]
Amdt. 27-26, E.. 4/5/90
63.8 Fatigue Evaluation
FAR 27.571 : Fatigue evaluation of .ight structure
(a) [General.Eachportionofthe .ightstructure(the .ightstructureincludesrotors, rotor drive systems between the engines and the rotor hubs, controls, fuselage, landinggear,and theirrelatedprimary attachments),thefailureof which couldbe catastrophic, mustbeidenti.ed and mustbe evaluated underparagraph(b),(c), (d), or(e)of this section.Thefollowing apply to eachfatigue evaluation:]
(1) The procedure for the evaluation must be approved.
(2)
The locations of probable failure must be determined.
(3)
In.ight measurement must be included in determining the following :
(i)
Loads or stresses in all critical conditions throughout the range of limita-tionsinSec.27.309, except that maneuveringloadfactors need not exceed the maximum values expected in operation.
(ii)
The e.ect of altitude upon these loads or stresses.
(4)
[The loadingspectra must be as severe as those expected in operation inclu-ding,but notlimited to, external cargooperations,if applicable, andground-air-ground cycles. The loading spectra must be based on loads or stresses determined underparagraph(a)(3) of this section.]
(b)
Fatigue tolerance evaluation.It mustbe shownthat thefatiguetolerance ofthe struc-ture ensures that theprobability of catastrophicfatigue failureis extremely remote without establishing replacement times, inspection intervals or other procedures under Sec. A27.4 of Appendix A.
(c)
Replacement time evaluation. It must be shown that the probability of catastrophic fatigue failure is extremely remote within a replacement time furnished under Sec. A27.4 of Appendix A.
(d)
Failsafe evaluation. The following apply to failsafe evaluation :
(1)
It mustbe shownthat allpartialfailures willbecome readilydetectable under inspection procedures furnished under A27.4 of Appendix A.
(2)
The interval between the time when any partial failure becomes readily de-tectable underparagraph(d)(1) ofthis section, andthe time when any such failure is expected to reduce the remaining strength of the structure to limit or maximum attainableloads(whicheverisless), mustbedetermined.
(3)
It mustbe shownthattheintervaldetermined underparagraph(d)(2) of this sectionislong enough,in relationtotheinspectionintervals and relatedpro-cedures furnished under A27.4 of Appendix A, to provide a probability of detection great enough to ensure that the probability of catastrophic failure is extremely remote.
(e)
Combination of replacement time and failsafe evaluations. A component may be evaluated under a combination ofparagraphs(c) and(d) ofthis section.For such componentit mustbe shownthattheprobability of catastrophicfailureis extremely remote with an approved combination of replacementtime,inspectionintervals, and related procedures furnished under A27.4 of Appendix A.
Amdt. 27-26, E.. 4/5/90
′
Elodie Roux. Septembre 2003
Subpart C : Strength Requirements
Chapitre 64
Subpart D : Design and Construction
Sommaire
64.1General ............................... 813
FAR27.601:Design ....................... 813 FAR27.602:[Criticalparts.] .................. 813 FAR27.603:Materials ..................... 813 FAR27.605:Fabricationmethods . . . . . . . . . . . . . . . 813 FAR27.607:[Fasteners.] .................... 813 FAR27.609:Protectionof structure . . . . . . . . . . . . . . 814 FAR27.610:[Lightning and staticelectricityprotection.] . . 814 FAR27.611:Inspectionprovisions . . . . . . . . . . . . . . . 814 FAR 27.613 : Material strength properties and design values . 815 FAR27.619:Specialfactors. . . . . . . . . . . . . . . . . . . 815 FAR27.621:Castingfactors .................. 816 FAR27.623:Bearingfactors .................. 817 FAR27.625:Fittingfactors. . . . . . . . . . . . . . . . . . . 817 FAR27.629:Flutter. . . . . . . . . . . . . . . . . . . . . . . 817 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：FAA规章 美国联邦航空规章 Federal Aviation Regulations 4(84)
