(i)
The load necessary to separate a breakaway coupling must be between 25 to50percent ofthe minimum ultimatefailureload(ultimate strength) of the weakest component in the .uid-carrying line. The separation load mustinnocasebelessthan300pounds,regardlessof thesizeof the .uid line.
(ii)
Abreakaway coupling must separatewheneverits ultimateload(asde.-nedinparagraph(c)(1)(i) of this section) is appliedinthefailure modes most likely to occur.
(iii) All breakaway couplings must incorporate design provisions to visually ascertainthatthe coupling islockedtogether(leak-free) andis opendu-ring normal installation and service.
(iv)
All breakaway couplings must incorporate design provisions to prevent uncoupling or unintended closing due to operational shocks, vibrations, or accelerations.
(v)
No breakaway coupling design may allow the release of fuel once the coupling has performed its intended function.
(2)
All individual breakaway couplings, coupling fuel feed systems, or equivalent means mustbe designed, tested, installed, and maintained so thatinadvertent fuel shuto.in .ightisimprobableinaccordancewithSec.27.955(a) and must comply with the fatigue evaluation requirements of Sec. 27.571 without lea-king.
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Elodie Roux. Septembre 2003
Subpart E : Powerplant
(3) Alternate, equivalent means to the use ofbreakaway couplings must not create a survivableimpact-inducedload on thefuelline to whichitisinstalledgreater than25to50percent ofthe ultimateload(strength) ofthe weakest component in the line and must comply with the fatigue requirements of Sec. 27.571 without leaking.
(d)
Frangible or deformable structural attachments. Unless hazardous relative motion of fuel tanks andfuel system components tolocal rotorcraft structureisdemonstrated to be extremely improbable in an otherwise survivable impact, frangible or locally deformable attachments offueltanks andfuelsystem componentstolocal rotorcraft structure mustbe used.The attachment offueltanks andfuel system componentsto localrotorcraft structure, whetherfrangible orlocallydeformable, mustbedesigned such that its separation or relative local deformation will occur without rupture or localtear-outofthefueltank orfuel system componentsthat will causefuelleakage. The ultimate strength of frangible or deformable attachments must be as follows :
(1)
The load required to separate a frangible attachment from its support struc-ture, or deform a locally deformable attachment relative to its support struc-ture, mustbebetween25 and50percent of the minimum ultimateload(ulti-mate strength) of the weakest component in the attached system. In no case may the load be less than 300pounds.
(2)
A frangible or locally deformable attachment must separate or locally deform asintended wheneverits ultimateload(asde.nedinparagraph(d)(1) of this section) is applied in the modes most likely to occur.
(3)
All frangible or locally deformable attachments must comply with the fatigue requirements of Sec. 27.571.
(e)
Separation of fuel and ignition sources. To provide maximum crash resistance, fuel mustbelocated asfar aspracticablefrom all occupiable areas andfrom allpotential ignition sources.
(f)
Other basic mechanical design criteria. Fuel tanks, fuel lines, electrical wires, and electricaldevices mustbedesigned, constructed, andinstalled, asfar aspracticable, to be crash resistant.
(g)
Rigid or Semirigid fuel tanks. Rigid or semirigid fuel tank or bladder walls must be
impact and tear resistant.] Amdt. 27-30, E.. 11/2/94
FAR 27.953 : Fuel system independence
(a)
Each fuel system for multiengine rotorcraft must allow fuel to be supplied to each engine through a system independent of those parts of each system supplying fuel to other engines.However, separatefuel tanks need notbeprovidedfor each engine.
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本文鏈接地址：FAA規(guī)章 美國(guó)聯(lián)邦航空規(guī)章 Federal Aviation Regulations 4(107)
