Federal Aviation Administration, DOT

Section 29.993

(b) Carburetor vapor vents. Each carburetor with vapor elimination connections must have a vent line to lead vapors back to one of the fuel tanks. In
addition - 
(1) Each vent system must have
means to avoid stoppage by ice; and
(2) If there is more than one fuel
tank, and it is necessary to use the
tanks in a definite sequence, each
vapor vent return line must lead back
to the fuel tank used for takeoff and
landing.
[Doc. No. 5084, 29 FR 16150, Dec. 3, 1964, as
amended by Amdt. 29-26, 53 FR 34217, Sept. 2,
1988; Amdt. 29-35, 59 FR 50388, Oct. 3, 1994;
Amdt. 29-42, 63 FR 43285, Aug. 12, 1998]

Section 29.977 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 engine powered
airplanes, have 8 to 16 meshes per inch;
and
(2) For turbine engine powered airplanes, prevent the passage of any object that could restrict fuel flow or
damage any fuel system component.
(b) The clear area of each fuel tank
outlet strainer must be at least five
times the area of the outlet line.
(c) The diameter of each strainer
must be at least that of the fuel tank
outlet.
(d) Each finger strainer must be accessible for inspection and cleaning.

spaschal on DSK3GDR082PROD with CFR

[Amdt. 29-12, 41 FR 55473, Dec. 20, 1976]

Section 29.979 Pressure refueling and fueling
provisions below fuel level.
(a) Each fueling connection below the
fuel level in each tank must have
means to prevent the escape of hazardous quantities of fuel from that
tank in case of malfunction of the fuel
entry valve.
(b) For systems intended for pressure
refueling, a means in addition to the
normal means for limiting the tank
content must be installed to prevent
damage to the tank in case of failure of
the normal means.
(c) The rotorcraft pressure fueling
system (not fuel tanks and fuel tank
vents) must withstand an ultimate
load that is 2.0 times the load arising
from the maximum pressure, including
surge, that is likely to occur during

fueling. The maximum surge pressure
must be established with any combination of tank valves being either intentionally or inadvertently closed.
(d) The rotorcraft defueling system
(not including fuel tanks and fuel tank
vents) must withstand an ultimate
load that is 2.0 times the load arising
from
the
maximum
permissible
defueling pressure (positive or negative) at the rotorcraft fueling connection.
[Doc. No. 5084, 29 FR 16150, Dec. 3, 1964, as
amended by Amdt. 29-12, 41 FR 55473, Dec. 20,
1976]

FUEL SYSTEM COMPONENTS
Section 29.991 Fuel pumps.
(a) Compliance with Section 29.955 must not
be jeopardized by failure of - 
(1) Any one pump except pumps that
are approved and installed as parts of a
type certificated engine; or
(2) Any component required for pump
operation except the engine served by
that pump.
(b) The following fuel pump installation requirements apply:
(1) When necessary to maintain the
proper fuel pressure - 
(i) A connection must be provided to
transmit the carburetor air intake
static pressure to the proper fuel pump
relief valve connection; and
(ii) The gauge balance lines must be
independently connected to the carburetor inlet pressure to avoid incorrect
fuel pressure readings.
(2) The installation of fuel pumps
having seals or diaphragms that may
leak must have means for draining
leaking fuel.
(3) Each drain line must discharge
where it will not create a fire hazard.
[Amdt. 29-26, 53 FR 34217, Sept. 2, 1988]

Section 29.993 Fuel system lines and fittings.
(a) Each fuel line must be installed
and supported to prevent excessive vibration and to withstand loads due to
fuel pressure, valve actuation, and accelerated flight conditions.
(b) Each fuel line connected to components of the rotorcraft between
which relative motion could exist must
have provisions for flexibility.
(c) Each flexible connection in fuel
lines that may be under pressure or

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