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14 CFR Ch. I (1–1–14 Edition)
§ 27.993
§ 27.993
Fuel system lines and fittings.
(a) Each fuel line must be installed
and supported to prevent excessive vi-
bration and to withstand loads due to
fuel pressure and accelerated flight
conditions.
(b) Each fuel line connected to com-
ponents of the rotorcraft between
which relative motion could exist must
have provisions for flexibility.
(c) Flexible hose must be approved.
(d) Each flexible connection in fuel
lines that may be under pressure or
subjected to axial loading must use
flexible hose assemblies.
(e) No flexible hose that might be ad-
versely affected by high temperatures
may be used where excessive tempera-
tures will exist during operation or
after engine shutdown.
[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964, as
amended by Amdt. 27–2, 33 FR 964, Jan. 26,
1968]
§ 27.995
Fuel valves.
(a) There must be a positive, quick-
acting valve to shut off fuel to each en-
gine individually.
(b) The control for this valve must be
within easy reach of appropriate crew-
members.
(c) Where there is more than one
source of fuel supply there must be
means for independent feeding from
each source.
(d) No shutoff valve may be on the
engine side of any firewall.
§ 27.997
Fuel strainer or filter.
There must be a fuel strainer or filter
between the fuel tank outlet and the
inlet of the first fuel system compo-
nent which is susceptible to fuel con-
tamination, including but not limited
to the fuel metering device or an en-
gine positive displacement pump,
whichever is nearer the fuel tank out-
let. This fuel strainer or filter must—
(a) Be accessible for draining and
cleaning and must incorporate a screen
or element which is easily removable;
(b) Have a sediment trap and drain
except that it need not have a drain if
the strainer or filter is easily remov-
able for drain purposes;
(c) Be mounted so that its weight is
not supported by the connecting lines
or by the inlet or outlet connections of
the strainer or filter itself, unless ade-
quate strength margins under all load-
ing conditions are provided in the lines
and connections; and
(d) Provide a means to remove from
the fuel any contaminant which would
jeopardize the flow of fuel through
rotorcraft or engine fuel system com-
ponents required for proper rotorcraft
fuel system or engine fuel system oper-
ation.
[Amdt. 27–9, 39 FR 35461, Oct. 1, 1974, as
amended by Amdt. 27–20, 49 FR 6849, Feb. 23,
1984; Amdt. 27–23, 53 FR 34213, Sept. 2, 1988]
§ 27.999
Fuel system drains.
(a) There must be at least one acces-
sible drain at the lowest point in each
fuel system to completely drain the
system with the rotorcraft in any
ground attitude to be expected in serv-
ice.
(b) Each drain required by paragraph
(a) of this section must—
(1) Discharge clear of all parts of the
rotorcraft;
(2) Have manual or automatic means
to assure positive closure in the off po-
sition; and
(3) Have a drain valve—
(i) That is readily accessible and
which can be easily opened and closed;
and
(ii) That is either located or pro-
tected to prevent fuel spillage in the
event of a landing with landing gear re-
tracted.
[Doc. No. 574, 29 FR 15695, Nov. 24, 1964, as
amended by Amdt. 27–11, 41 FR 55470, Dec. 20,
1976; Amdt. 27–23, 53 FR 34213, Sept. 2, 1988]
O
IL
S
YSTEM
§ 27.1011
Engines: General.
(a) Each engine must have an inde-
pendent oil system that can supply it
with an appropriate quantity of oil at a
temperature not above that safe for
continuous operation.
(b) The usable oil capacity of each
system may not be less than the prod-
uct of the endurance of the rotorcraft
under critical operating conditions and
the maximum oil consumption of the
engine under the same conditions, plus
a suitable margin to ensure adequate
circulation and cooling. Instead of a ra-
tional analysis of endurance and con-
sumption, a usable oil capacity of one
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