(3)
For castings procured to a speci.cation that guarantees the mechanical pro-perties of the material in the casting and provides for demonstration of these properties by test of coupons cut from the castings on a sampling basis–
(i)
A casting factor of1.0 may be used; and
(ii)
The castings mustbeinspected asprovidedin subparagraph(1) of this paragraph for casting factors of ”1.25 through 1.50” and tested under paragraph(c)(2) of this section.
Casting factor Inspection
2.0 or more 100 percent visual
Less than 2.0 but more than 1.5 100 percent visual, and magne-tic particle or penetrant or equi-valent nondestructive inspection methods.
1.25 through 1.50 100percentvisual, magnetic par-ticle or penetrant, and radio-graphic, or approved equivalent nondestructive inspection me-thods.
FAR 25.623 : Bearing factors.
(a)
Except asprovidedinparagraph(b) ofthis section, eachpartthathas clearance (free .t), andthat is subject to pounding or vibration, must have a bearing factor large enough to provide for the e.ects of normal relative motion.
(b)
No bearing factor need be used for a part for which any larger special factor is prescribed.
FAR 25.625 : Fitting factors.
Foreach .tting(apartorterminal usedtojoinonestructural membertoanother), the following apply :
(a)
Foreach.ttingwhosestrengthisnotprovenbylimit and ultimateloadtestsinwhich actual stress conditions are simulated in the .tting and surrounding structures, a .tting factor of at least 1.15 must be applied to each part of–
(1)
The .tting;
(2)
The means of attachment; and
(3)
Thebearing onthejoined members.
(b)
No .tting factor need be used–
′
Elodie Roux. Septembre 2003
Subpart D : Design and Construction
(1)
For joints made under approved practices and based on comprehensive test data(such as continuousjointsin metalplating, weldedjoints, and scarfjoints in wood); or
(2)
With respect to any bearing surface for which a larger special factor is used.
(c)
For each integral .tting, the part must be treated as a .tting up to the point at which the section properties become typical of the member.
(d)
[For each seat, berth, safety belt, and harness, the .tting factor speci.ed in Sec.
25.785(f)(3) applies.] Amdt. 25-72, E.. 8/20/90
FAR25.629 :[Aeroelastic stability requirements.]
(a)
[General. The aeroelastic stability evaluations required under this section include .utter, divergence, control reversal and any undue loss of stability and control as a result of structural deformation. The aeroelastic evaluation must include whirl modes associated with anypropeller or rotating devicethat contributes signi.cant dynamic forces. Compliance with this section must be shown by analyses, wind tunnel tests,ground vibrationtests, .ighttests,orothermeansfound necessaryby the Administrator.
(b)
Aeroelastic stability envelopes. The airplane must be designed to be free from aeroe-lastic instability for all con.gurations and design conditions within the aeroelastic stability envelopes as follows :
(1)
For normalconditions withoutfailures, malfunctions, or adverse conditions, all combinationsof altitudes and speedsencompassedby the VD/MD versus alti-tude envelopeenlarged at allpointsby anincreaseof15percentin equivalent airspeed at both constant Mach number and constant altitude. In addition, a proper margin of stability must exist at all speeds up to VD/MD and, there must be no large and rapid reduction in stability as VD/MD is approached. The enlarged envelope may be limited to Mach 1.0 when MD is less than 1.0 at all design altitudes, and
(2)
For the conditionsdescribedinSec.25.659(d)below,for allapproved altitudes, any airspeed up to the greater airspeed de.ned by :
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本文链接地址：FAA规章 美国联邦航空规章 Federal Aviation Regulations 3(73)
