Code of Federal Regulations - Title 14

785

Federal Aviation Administration, DOT

§ 29.979

(1) Each filler must be marked as pre-

scribed in § 29.1557(c)(1);

(2) Each recessed filler connection

that can retain any appreciable quan-
tity of fuel must have a drain that dis-
charges clear of the entire rotorcraft;
and

(3) Each filler cap must provide a

fuel-tight seal under the fluid pressure
expected in normal operation and in a
survivable impact.

(b) Each filler cap or filler cap cover

must warn when the cap is not fully
locked or seated on the filler connec-
tion.

[Doc. No. 26352, 59 FR 50388, Oct. 3, 1994]

§ 29.975

Fuel tank vents and carbu-

retor vapor vents.

(a)

Fuel tank vents. Each fuel tank

must be vented from the top part of the
expansion space so that venting is ef-
fective under normal flight conditions.
In addition—

(1) The vents must be arranged to

avoid stoppage by dirt or ice forma-
tion;

(2) The vent arrangement must pre-

vent siphoning of fuel during normal
operation;

(3) The venting capacity and vent

pressure levels must maintain accept-
able differences of pressure between
the interior and exterior of the tank,
during—

(i) Normal flight operation;
(ii) Maximum rate of ascent and de-

scent; and

(iii) Refueling and defueling (where

applicable);

(4) Airspaces of tanks with inter-

connected outlets must be inter-
connected;

(5) There may be no point in any vent

line where moisture can accumulate
with the rotorcraft in the ground atti-
tude or the level flight attitude, unless
drainage is provided;

(6) No vent or drainage provision may

end at any point—

(i) Where the discharge of fuel from

the vent outlet would constitute a fire
hazard; or

(ii) From which fumes could enter

personnel compartments; and

(7) The venting system must be de-

signed to minimize spillage of fuel
through the vents to an ignition source
in the event of a rollover during land-

ing, ground operations, or a survivable
impact.

(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

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