FAR 25.977 : Fuel tank outlet.
(a)
There must be a fuel strainer for the fuel tank outlet or for the booster pump. This strainer must–
(1)
For reciprocating enginepowered airplanes,have8 to 16 meshesper inch; and
(2)
For turbine engine powered airplanes, prevent the passage of any object that could restrict fuel .ow or damage any fuel system component.
(b)
[[Reserved.]]
(c)
The clear area of each fuel tank outlet strainer must be at least .ve times the area of the outlet line.
(d)
The diameter of each strainer must be at least that of the fuel tank outlet.
(e)
Each .nger strainer must be accessible for inspection and cleaning. Amdt. 25-36, E.. 10/31/74
FAR 25.979 : Pressure fueling system.
For pressure fueling systems, the following apply :
(a)
Each pressure fueling system fuel manifold connection must have means to prevent the escape of hazardous quantities of fuel from the system if the fuel entry valve fails.
(b)
An automatic shuto. means mustbeprovidedtoprevent thequantity offuelin each tank from exceeding the maximum quantity approved for that tank. This means must–
(1)
Allow checking for proper shuto. operation before each fueling of the tank; and
(2)
[Provide indication at each fueling station of failure of the shuto. means to stop the fuel .ow at the maximum quantity approved for that tank.]
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Elodie Roux. Septembre 2003
Subpart E : Powerplant
(c)
A means must be provided to prevent damage to the fuel system in the event of failure of the automatic shuto. meansprescribedinparagraph(b) of this section.
(d)
The airplanepressurefueling system(notincluding fueltanks andfueltank vents) must withstand an ultimate load that is 2.0 times the load arising from the maxi-mumpressures,including surge,thatislikelyto occurduringfueling.The maximum surgepressure mustbe established with any combination oftank valvesbeing either intentionally or inadvertently closed.
(e)
Theairplanedefueling system(notincludingfueltanksandfueltank vents) must withstand an ultimate load that is 2.0 times the load arising from the maximum permissible defuelingpressure(positive or negative) at the airplane fueling connec-tion.
Amdt. 25-72, E.. 8/20/90
FAR25.981 :Fuel tank[ignitionprevention.]
(a)
[No ignition source maybepresentat eachpoint in the fuel tank orfuel tank system where catastrophic failure could occur due to ignition of fuel or vapors. This must be shown by :
(1)
Determining the highest temperature allowing a safe margin below the lowest expected autoignition temperature of the fuel in the fuel tanks.
(2)
Demonstrating that no temperature at each place inside each fuel tank where fuel ignition is possible will exceed the temperature determined under para-graph(a)(1)ofthis section.This mustbe veri.ed under allprobable operating, failure, and malfunction conditions of each component whose operation, fai-lure, or malfunction could increase the temperature inside the tank.
(3)
Demonstratingthat anignition source could not resultfrom each singlefailure, from each single failure in combination with each latent failure condition not shown tobe extremely remote, andfrom all combinations offailures not shown to be extremely improbable. The e.ects of manufacturing variability, aging, wear, corrosion, and likely damage must be considered.
(b)
Basedonthe evaluations requiredbythis section, criticaldesign con.gurationcontrol limitations, inspections, or other procedures must be established, as necessary, to prevent development of ignition sources within the fuel tank system and must be included in the AirworthinessLimitations section of the InstructionsforContinued Airworthiness required by Sec. 25.1529. Visible means to identify critical features of the design must be placed in areas of the airplane where maintenance actions, repairs, or alterations may be apt to violate the critical design con.guration limi-tations(e.g., color-coding of wiretoidentify separationlimitation).
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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(118)
