title-14-part-29-sec29-1109

646

14 CFR Ch. I (1–1–24 Edition)

§ 29.1101

section if the heat rise utilized is that
which will be available, automatically,
for the applicable altitude and oper-
ation condition because of super-
charging.

(Secs. 313(a), 601, and 603, 72 Stat. 752, 775, 49
U.S.C. 1354(a), 1421, and 1423; sec. 6(c), 49
U.S.C. 1655 (c))

[Amdt. 29–3, 33 FR 969, Jan. 26, 1968, as
amended by Amdt. 29–12, 41 FR 55473, Dec. 20,
1976; Amdt. 29–13, 42 FR 15046, Mar. 17, 1977;
Amdt. 29–22, 49 FR 6850, Feb. 23, 1984; Amdt.
29–26, 53 FR 34219, Sept. 2, 1988]

§ 29.1101

Carburetor air preheater de-

sign.

Each carburetor air preheater must

be designed and constructed to—

(a) Ensure ventilation of the pre-

heater when the engine is operated in
cold air;

(b) Allow inspection of the exhaust

manifold parts that it surrounds; and

of the preheater itself.

§ 29.1103

Induction systems ducts and

air duct systems.

(a) Each induction system duct up-

stream of the first stage of the engine
supercharger and of the auxiliary
power unit compressor must have a
drain to prevent the hazardous accu-
mulation of fuel and moisture in the
ground attitude. No drain may dis-
charge where it might cause a fire haz-
ard.

(b) Each duct must be strong enough

to prevent induction system failure
from normal backfire conditions.

nents between which relative motion
could exist must have means for flexi-
bility.

(d) Each duct within any fire zone for

which a fire-extinguishing system is re-
quired must be at least—

(1) Fireproof, if it passes through any

firewall; or

(2) Fire resistant, for other ducts, ex-

cept that ducts for auxiliary power
units must be fireproof within the aux-
iliary power unit fire zone.

(e) Each auxiliary power unit induc-

tion system duct must be fireproof for
a sufficient distance upstream of the
auxiliary power unit compartment to
prevent hot gas reverse flow from burn-
ing through auxiliary power unit ducts

and entering any other compartment
or area of the rotorcraft in which a
hazard would be created resulting from
the entry of hot gases. The materials
used to form the remainder of the in-
duction system duct and plenum cham-
ber of the auxiliary power unit must be
capable of resisting the maximum heat
conditions likely to occur.

(f) Each auxiliary power unit induc-

tion system duct must be constructed
of materials that will not absorb or
trap hazardous quantities of flammable
fluids that could be ignited in the
event of a surge or reverse flow condi-
tion.

(Secs. 313(a), 601, 603, 604, Federal Aviation
Act of 1958 (49 U.S.C. 1354(a), 1421, 1423, 1424),
sec. 6(c), Dept. of Transportation Act (49
U.S.C. 1655(c)))

[Doc. No. 5084, 29 FR 16150, Dec. 3, 1964, as
amended by Amdt. 29–17, 43 FR 50602, Oct. 30,
1978]

§ 29.1105

Induction system screens.

If induction system screens are

used—

(a) Each screen must be upstream of

the carburetor;

(b) No screen may be in any part of

the induction system that is the only
passage through which air can reach
the engine, unless it can be deiced by
heated air;

hol alone; and

(d) It must be impossible for fuel to

strike any screen.

§ 29.1107

Inter-coolers and after-cool-

ers.

Each inter-cooler and after-cooler

must be able to withstand the vibra-
tion, inertia, and air pressure loads to
which it would be subjected in oper-
ation.

§ 29.1109

Carburetor air cooling.

It must be shown under § 29.1043 that

each installation using two-stage su-
perchargers has means to maintain the
air temperature, at the carburetor
inlet, at or below the maximum estab-
lished value.

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§ 29.1125

XHAUST

YSTEM

§ 29.1121

General.

For powerplant and auxiliary power

unit installations the following apply:

(a) Each exhaust system must ensure

safe disposal of exhaust gases without
fire hazard or carbon monoxide con-
tamination in any personnel compart-
ment.

(b) Each exhaust system part with a

surface hot enough to ignite flammable
fluids or vapors must be located or
shielded so that leakage from any sys-
tem carrying flammable fluids or va-
pors will not result in a fire caused by
impingement of the fluids or vapors on
any part of the exhaust system includ-
ing shields for the exhaust system.

exhaust gases could impinge, or that
could be subjected to high tempera-
tures from exhaust system parts, must
be fireproof. Each exhaust system com-
ponent must be separated by a fire-
proof shield from adjacent parts of the
rotorcraft that are outside the engine
and auxiliary power unit compart-
ments.

(d) No exhaust gases may discharge

so as to cause a fire hazard with re-
spect to any flammable fluid vent or
drain.

(e) No exhaust gases may discharge

where they will cause a glare seriously
affecting pilot vision at night.

(f) Each exhaust system component

must be ventilated to prevent points of
excessively high temperature.

(g) Each exhaust shroud must be ven-

tilated or insulated to avoid, during
normal operation, a temperature high
enough to ignite any flammable fluids
or vapors outside the shroud.

(h) If significant traps exist, each

turbine engine exhaust system must
have drains discharging clear of the
rotorcraft, in any normal ground and
flight attitudes, to prevent fuel accu-
mulation after the failure of an at-
tempted engine start.

(Secs. 313(a), 601, and 603, 72 Stat. 752, 755, 49
U.S.C. 1354(a), 1421, and 1423; sec. 6(c), 49
U.S.C. 1655 (c))

[Doc. No. 5084, 29 FR 16150, Dec. 3, 1964, as
amended by Amdt. 29–3, 33 FR 970, Jan. 26,
1968; Amdt. 29–13, 42 FR 15046, Mar. 17, 1977]

§ 29.1123

Exhaust piping.

(a) Exhaust piping must be heat and

corrosion resistant, and must have pro-
visions to prevent failure due to expan-
sion by operating temperatures.

(b) Exhaust piping must be supported

to withstand any vibration and inertia
loads to which it would be subjected in
operation.

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

§ 29.1125

Exhaust heat exchangers.

For reciprocating engine powered

rotorcraft the following apply:

(a) Each exhaust heat exchanger

must be constructed and installed to
withstand the vibration, inertia, and
other loads to which it would be sub-
jected in operation. In addition—

(1) Each exchanger must be suitable

for continued operation at high tem-
peratures and resistant to corrosion
from exhaust gases;

(2) There must be means for inspect-

ing the critical parts of each ex-
changer;

(3) Each exchanger must have cooling

provisions wherever it is subject to
contact with exhaust gases; and

(4) No exhaust heat exchanger or

muff may have stagnant areas or liquid
traps that would increase the prob-
ability of ignition of flammable fluids
or vapors that might be present in case
of the failure or malfunction of compo-
nents carrying flammable fluids.

(b) If an exhaust heat exchanger is

used for heating ventilating air used by
personnel—

(1) There must be a secondary heat

exchanger between the primary ex-
haust gas heat exchanger and the ven-
tilating air system; or

(2) Other means must be used to pre-

vent harmful contamination of the
ventilating air.

[Doc. No. 5084, 29 FR 16150, Dec. 3, 1964, as
amended by Amdt. 29–12, 41 FR 55473, Dec. 20,
1976; Amdt. 29–41, 62 FR 46173, Aug. 29, 1997]