spaschal on DSK3GDR082PROD with CFR

Section 29.952

14 CFR Ch. I (1-1-19 Edition)

(2) For fuel tanks located above or
behind the crew or passenger compartment that, if loosened, could injure an
occupant in an emergency landing:
(i) Upward - 1.5g.
(ii) Forward - 8g.
(iii) Sideward - 2g.
(iv) Downward - 4g.
(3) For fuel tanks in other areas:
(i) Upward - 1.5g.
(ii) Forward - 4g.
(iii) Sideward - 2g.
(iv) Downward - 4g.
(c) Fuel line self-sealing breakaway
couplings. Self-sealing breakaway couplings must be installed unless hazardous relative motion of fuel system
components to each other or to local
rotorcraft structure is demonstrated to
be extremely improbable or unless
other means are provided. The couplings or equivalent devices must be
installed at all fuel tank-to-fuel line
connections, tank-to-tank interconnects, and at other points in the fuel
system where local structural deformation could lead to the release of fuel.
(1) The design and construction of
self-sealing breakaway couplings must
incorporate the following design features:
(i) The load necessary to separate a
breakaway coupling must be between
25 to 50 percent of the minimum ultimate failure load (ultimate strength)
of the weakest component in the fluidcarrying line. The separation load
must in no case be less than 300 pounds,
regardless of the size of the fluid line.
(ii) A breakaway coupling must separate whenever its ultimate load (as defined in paragraph (c)(1)(i) of this section) is applied in the failure modes
most likely to occur.
(iii) All breakaway couplings must
incorporate design provisions to visually ascertain that the coupling is
locked together (leak-free) and is open
during 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 must be designed,
tested, installed, and maintained so inadvertent fuel shutoff in flight is improbable in accordance with Section 29.955(a)
and must comply with the fatigue evaluation requirements of Section 29.571 without
leaking.
(3) Alternate, equivalent means to
the use of breakaway couplings must
not create a survivable impact-induced
load on the fuel line to which it is installed greater than 25 to 50 percent of
the ultimate load (strength) of the
weakest component in the line and
must comply with the fatigue requirements of Section 29.571 without leaking.
(d) Frangible or deformable structural
attachments. Unless hazardous relative
motion of fuel tanks and fuel system
components to local rotorcraft structure is demonstrated to be extremely
improbable in an otherwise survivable
impact, frangible or locally deformable
attachments of fuel tanks and fuel system components to local rotorcraft
structure must be used. The attachment of fuel tanks and fuel system
components to local rotorcraft structure, whether frangible or locally deformable, must be designed such that
its separation or relative local deformation will occur without rupture or
local tear-out of the fuel tank or fuel
system component that will cause fuel
leakage. The ultimate strength of frangible or deformable attachments must
be as follows:
(1) The load required to separate a
frangible attachment from its support
structure, or deform a locally deformable attachment relative to its support
structure, must be between 25 and 50
percent of the minimum ultimate load
(ultimate strength) of the weakest
component in the attached system. In
no case may the load be less than 300
pounds.
(2) A frangible or locally deformable
attachment must separate or locally
deform as intended whenever its ultimate load (as defined in paragraph
(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 Section 29.571.

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