Federal Aviation Administration, DOT

Section 29.1121

for the applicable altitude and operation condition because of supercharging.
(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]

spaschal on DSK3GDR082PROD with CFR

Section 29.1101 Carburetor air preheater design.
Each carburetor air preheater must
be designed and constructed to - 
(a) Ensure ventilation of the preheater when the engine is operated in
cold air;
(b) Allow inspection of the exhaust
manifold parts that it surrounds; and
(c) Allow inspection of critical parts
of the preheater itself.
Section 29.1103 Induction systems ducts and
air duct systems.
(a) Each induction system duct upstream of the first stage of the engine
supercharger and of the auxiliary
power unit compressor must have a
drain to prevent the hazardous accumulation of fuel and moisture in the
ground attitude. No drain may discharge where it might cause a fire hazard.
(b) Each duct must be strong enough
to prevent induction system failure
from normal backfire conditions.
(c) Each duct connected to components between which relative motion
could exist must have means for flexibility.
(d) Each duct within any fire zone for
which a fire-extinguishing system is required must be at least - 
(1) Fireproof, if it passes through any
firewall; or
(2) Fire resistant, for other ducts, except that ducts for auxiliary power
units must be fireproof within the auxiliary power unit fire zone.
(e) Each auxiliary power unit induction system duct must be fireproof for
a sufficient distance upstream of the
auxiliary power unit compartment to
prevent hot gas reverse flow from burning 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 induction system duct and plenum chamber of the auxiliary power unit must be
capable of resisting the maximum heat
conditions likely to occur.
(f) Each auxiliary power unit induction 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 condition.
(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]

Section 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;
(c) No screen may be deiced by alcohol alone; and
(d) It must be impossible for fuel to
strike any screen.
Section 29.1107
ers.

Inter-coolers and after-cool-

Each inter-cooler and after-cooler
must be able to withstand the vibration, inertia, and air pressure loads to
which it would be subjected in operation.
Section 29.1109

Carburetor air cooling.

It must be shown under Section 29.1043 that
each installation using two-stage superchargers has means to maintain the
air temperature, at the carburetor
inlet, at or below the maximum established value.
EXHAUST SYSTEM
Section 29.1121

General.

For powerplant and auxiliary power
unit installations the following apply:

645

VerDate Sep<11>2014

12:50 Apr 30, 2019

Jkt 247046

PO 00000

Frm 00655

Fmt 8010

Sfmt 8010

Y:\SGML\247046.XXX

247046