title-14-part-29-sec29-1093

645

Federal Aviation Administration, DOT

§ 29.1093

(b) With maximum continuous power,

maximum weight, and at the altitude
resulting in zero rate of climb for this
configuration, until at least five min-
utes after the occurrence of the highest
temperature recorded.

NDUCTION

YSTEM

§ 29.1091

Air induction.

(a) The air induction system for each

engine and auxiliary power unit must
supply the air required by that engine
and auxiliary power unit under the op-
erating conditions for which certifi-
cation is requested.

(b) Each engine and auxiliary power

unit air induction system must provide
air for proper fuel metering and mix-
ture distribution with the induction
system valves in any position.

the engine accessory section or within
other areas of any powerplant compart-
ment where emergence of backfire
flame would constitute a fire hazard.

(d) Each reciprocating engine must

have an alternate air source.

(e) Each alternate air intake must be

located to prevent the entrance of rain,
ice, or other foreign matter.

(f) For turbine engine powered rotor-

craft and rotorcraft incorporating aux-
iliary power units—

(1) There must be means to prevent

hazardous quantities of fuel leakage or
overflow from drains, vents, or other
components of flammable fluid systems
from entering the engine or auxiliary
power unit intake system; and

(2) The air inlet ducts must be lo-

cated or protected so as to minimize
the ingestion of foreign matter during
takeoff, landing, and taxiing.

(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. 29–3, 33 FR 969, Jan. 26,
1968; Amdt. 29–17, 43 FR 50601, Oct. 30, 1978]

§ 29.1093

Induction system icing pro-

tection.

(a)

Reciprocating engines. Each recip-

rocating engine air induction system
must have means to prevent and elimi-
nate icing. Unless this is done by other
means, it must be shown that, in air

free of visible moisture at a tempera-
ture of 30

F., and with the engines at

60 percent of maximum continuous
power—

(1) Each rotorcraft with sea level en-

gines using conventional venturi car-
buretors has a preheater that can pro-
vide a heat rise of 90

F.;

(2) Each rotorcraft with sea level en-

gines using carburetors tending to pre-
vent icing has a preheater that can
provide a heat rise of 70

F.;

(3) Each rotorcraft with altitude en-

gines using conventional venturi car-
buretors has a preheater that can pro-
vide a heat rise of 120

F.; and

(4) Each rotorcraft with altitude en-

gines using carburetors tending to pre-
vent icing has a preheater that can
provide a heat rise of 100

(b)

Turbine engines. (1) It must be

shown that each turbine engine and its
air inlet system can operate through-
out the flight power range of the en-
gine (including idling)—

(i) Without accumulating ice on en-

gine or inlet system components that
would adversely affect engine oper-
ation or cause a serious loss of power
under the icing conditions specified in
appendix C of this Part; and

(ii) In snow, both falling and blowing,

without adverse effect on engine oper-
ation, within the limitations estab-
lished for the rotorcraft.

(2) Each turbine engine must idle for

30 minutes on the ground, with the air
bleed available for engine icing protec-
tion at its critical condition, without
adverse effect, in an atmosphere that is
at a temperature between 15

and 30

(between

and

C) and has a liq-

uid water content not less than 0.3
grams per cubic meter in the form of
drops having a mean effective diameter
not less than 20 microns, followed by
momentary operation at takeoff power
or thrust. During the 30 minutes of idle
operation, the engine may be run up
periodically to a moderate power or
thrust setting in a manner acceptable
to the Administrator.

(c)

Supercharged reciprocating engines.

For each engine having a supercharger
to pressurize the air before it enters
the carburetor, the heat rise in the air
caused by that supercharging at any
altitude may be utilized in determining
compliance with paragraph (a) of this

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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.