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637

Federal Aviation Administration, DOT

§ 29.993

(b)

Carburetor vapor vents.

Each car-

buretor with vapor elimination connec-
tions must have a vent line to lead va-
pors 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]

§ 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 air-

planes, prevent the passage of any ob-
ject 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.

must be at least that of the fuel tank
outlet.

(d) Each finger strainer must be ac-

cessible for inspection and cleaning.

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

§ 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 haz-
ardous 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.

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 combina-
tion of tank valves being either inten-
tionally 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 nega-
tive) at the rotorcraft fueling connec-
tion.

[Doc. No. 5084, 29 FR 16150, Dec. 3, 1964, as
amended by Amdt. 29–12, 41 FR 55473, Dec. 20,
1976]

UEL

YSTEM

OMPONENTS

§ 29.991

Fuel pumps.

(a) Compliance with § 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 installa-

tion 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 carbu-
retor 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]

§ 29.993

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, valve actuation, and ac-
celerated flight conditions.

(b) Each fuel line connected to com-

ponents of the rotorcraft between
which relative motion could exist must
have provisions for flexibility.

lines that may be under pressure or

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