Federal Aviation Administration, DOT

Section 27.1011

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 adversely affected by high temperatures
may be used where excessive temperatures 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]

spaschal on DSK3GDR082PROD with CFR

Section 27.995 Fuel valves.
(a) There must be a positive, quickacting valve to shut off fuel to each engine individually.
(b) The control for this valve must be
within easy reach of appropriate crewmembers.
(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.
Section 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 component which is susceptible to fuel contamination, including but not limited
to the fuel metering device or an engine positive displacement pump,
whichever is nearer the fuel tank outlet. 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 removable 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 adequate strength margins under all loading 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 components required for proper rotorcraft

fuel system or engine fuel system operation.
[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]

Section 27.999

Fuel system drains.

(a) There must be at least one accessible 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 service.
(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 position; 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 protected to prevent fuel spillage in the
event of a landing with landing gear retracted.
[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]

OIL SYSTEM
Section 27.1011

Engines: General.

(a) Each engine must have an independent 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 product 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 rational analysis of endurance and consumption, a usable oil capacity of one
gallon for each 40 gallons of usable fuel
may be used.
(c) The oil cooling provisions for each
engine must be able to maintain the oil
inlet temperature to that engine at or

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