(b)
Material strength properties must be based on enough tests of material conforming to speci.cations so as to establish design values on a statistical basis.
FAR 31.35 : Fabrication methods.
The methods of fabrication used must produce a consistently sound structure. If a fabrication process requires close control to reach this objective, the process must be performedin accordance with an approvedprocess speci.cation.
FAR 31.37 : Fastenings.
Only approvedbolts,pins, screws, and rivets may be used in the structure.Approved locking devices or methods must be used for all these bolts, pins, and screws, unless the installationis shown tobefreefrom vibration.Self-lockingnuts may notbe used onbolts that are subject to rotation in service.
FAR 31.39 : Protection.
Each part of the balloon must be suitably protected against deterioration or loss of strength in service due to weathering, corrosion, or other causes.
FAR 31.41 : Inspection provisions.
There mustbe a means to allow close examination of eachpart that requires repeated inspection and adjustment.
FAR 31.43 : Fitting factor.
(a)
A .tting factor of at least 1.15 must be used in the analysis of each .tting the strength of which is notprovenbylimit and ultimate load testsin which the actual stressconditionsaresimulatedinthe .tting and surrounding structure.Thisfactor appliestoallpartsof the .tting,themeansof attachment,and thebearing onthe membersjoined.
(b)
Eachpartwith anintegral.tting mustbetreated asa .tting up tothepointwhere the section properties become typical of the member.
(c)
The .ttingfactorneednotbeusedifthejointdesignismadeinaccordancewith approvedpractices andisbased on comprehensivetestdata.
FAR 31.45 : Fuel cells.
[Iffuelcells are used, thefuel cells, their attachments and related supporting structure must be shown by tests to be capable of withstanding, without detrimental distortion or failure, any inertia loads to which the installation may be subjected, including the drop testsprescribedinSec.31.27(c).Inthetests,thefuel cells mustbeloaded tothe weight and pressure equivalent to the full fuel quantity condition.] Amdt. 31-3, E.. 2/1/77
FAR31.46 :[Pressurizedfuel systems.]
[ For pressurized fuel systems, each element and its connecting .ttings and lines mustbetested to an ultimatepressure of atleasttwicethe maximumpressureto which the system will be subjected in normal operation. No part of the system may fail or malfunction during the test. The test con.guration must be representative of the normal fuel system installation and balloon con.guration.] Amdt. 31-3, E.. 2/1/77
FAR31.47 :[Burners.]
(a)
[If a burner is used to provide the lifting means, the system must be designed and installed so as not to create a .re hazard.]
(b)
There must be shielding to protect parts adjacent to the burner .ame, and the occupants, from heat e.ects.
(c)
There mustbe controls,instruments, or other equipment essential to the safe control and operation of the heater. They must be shown to be able to perform their intended functions during normal and emergency operation.
(d)
[The burner system (including the burner unit, controls, fuel lines, fuel cells, re-gulators, control valves, and other related elements) must be substantiated by an endurance test of at least 40 hours. Each element of the system must be installed and tested to simulate actual balloon installation and use.
(1) The test program for the main blast valve operation of the burner must in-clude :
(i)
Five hours at the maximum fuel pressure for which approval is sought, with a burn time for each one minute cycle of three to ten seconds. The burn time must be established so that each burner is subjected to the maximumthermal shockfortemperature a.ected elements;
(ii)
Seven and one-half hours at an intermediate fuel pressure, with a burn time for each one minute cycle of three to ten seconds. An intermediate fuel pressure is 40 to 60 percent of the range between the maximum fuel pressure referenced in paragraph (d)(1)(i) and minimum fuel pressure referenced in paragraph(d)(1)(iii);
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本文链接地址：FAA规章 美国联邦航空规章 Federal Aviation Regulations 5(119)
