(i)
The identi.cation of principal structural elements, the failure of which could result in catastrophic failure of the rotorcraft;
(ii)
In-.ight measurement in determining the loads or stresses for items in paragraph(a)(1)(i)of this sectionin all critical conditions throughout the range oflimitations in Sec. 29.309(including altitude e.ects), except that maneuvering load factors need not exceed the maximum values expected in operations; and
(iii) Loading spectra as severe as those expected in operation based on loads or stressesdetermined underparagraph(a)(1)(ii) ofthis section,including external load operations, if applicable, and other high frequency power cycle operations.
(2)
Based on the evaluations required by this section, inspections, replacement times, combinations thereof, or other procedures must be established as ne-cessary to avoid catastrophic failure. These inspections, replacement times, combinations thereof, or other procedures must be included in the airwor-thiness limitations section of the Instructions for Continued Airworthiness required by Sec. 29.1529 and Section A29.4 of Appendix A of this part.
(b) Fatigue tolerance evaluation (including tolerance to .aws). The structure must be shown by analysis supported by test evidence and, if available, service experience to be of fatigue tolerant design. The fatigue tolerance evaluation must include the requirements of eitherparagraph(b)(1),(2), or(3) of this section, or a combination thereof, and also mustinclude adetermination of theprobablelocations and modes of damage caused by fatigue, considering environmental e.ects, intrinsic/discrete .aws,oraccidentaldamage.Compliancewiththe .awtolerancerequirementsofpa-ragraph(b)(1) or(2) of this sectionis required unless the applicant establishes that these fatigue .aw tolerant methods for a particular structure cannot be achieved within the limitations of geometry, inspectability, or good design practice. Under thesecircumstances,the safe-lifeevaluationofparagraph(b)(3) ofthissectionis required.
(1)
Flaw tolerant safe-life evaluation. It must be shown that the structure, with .aws present, is able to withstand repeated loads of variable magnitude wi-thout detectable .aw growth for the following time intervals–
(i)
Life of the rotorcraft; or
(ii)
Within a replacement time furnished under Section A29.4 of Appendix A to this part.
(2)
Fail-safe (residual strength after .aw growth) evaluation. It must be shown thatthe structureremaining after apartialfailureis abletowithstanddesign limitloads withoutfailure within aninspectionperiodfurnishedunderSection A29.4 of Appendix A to this part. Limit loads are de.ned in Sec. 29.301(a).
(i)
The residual strength evaluation must show that the remaining structure after .aw growth is able to withstand design limit loads without failure within its operational life.
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本文鏈接地址：FAA規(guī)章 美國聯(lián)邦航空規(guī)章 Federal Aviation Regulations 5(32)
