260
14 CFR Ch. I (1–1–19 Edition)
Pt. 121, App. C
(b)
Combustion heater compartments
All
lines, hoses, and end fittings, and couplings
which carry fuel to the heaters and heater
controls, must be of FAA approved fire-re-
sistant construction.
24.
Vent and drain lines
—(a)
Enginecompartment.
C–46 engine compart-
ments meet the requirements of § 121.261 if—
(1) The compartments conform to type de-
sign and comply with all applicable air-
worthiness directives or FAA approved
equivalent; and
(2) Drain lines from supercharger case, en-
gine-driven fuel pump, and engine-driven hy-
draulic pump reach into the scupper drain lo-
cated in the lower cowling segment.
(b)
Combustion heater compartment.
C–46
heater compartments meet the requirements
of § 121.261 if they conform to AD–49–18–1 or
FAA approved equivalent.
25.
Fire-extinguishing system.
(a) To meet
the requirements of § 121.263, C–46 airplanes
must have installed fire extinguishing sys-
tems to serve all designated fire zones. The
fire-extinguishing systems, the quantity of
extinguishing agent, and the rate of dis-
charge shall be such as to provide a min-
imum of one adequate discharge for each
designated fire zone. Compliance with this
provision requires the installation of a sepa-
rate fire extinguisher for each engine com-
partment. Insofar as the engine compart-
ment is concerned, the system shall be capa-
ble of protecting the entire compartment
against the various types of fires likely to
occur in the compartment.
(b) Fire-extinguishing systems which con-
form to the C–46 transport category require-
ments meet the requirements set forth in
paragraph (a). Furthermore, fire-extin-
guishing systems for combustion heater
compartments which conform to the require-
ments of AD–49–18–1 or an FAA approved
equivalent also meet the requirements in
paragraph (a).
In addition, a fire-extinguishing system for
C–46 airplanes meets the adequacy require-
ment of paragraph (a) if it provides the same
or equivalent protection to that dem-
onstrated by the CAA in tests conducted in
1941 and 1942, using a CW–20 type engine na-
celle (without diaphragm). These tests were
conducted at the Bureau of Standards facili-
ties in Washington, DC, and copies of the
test reports are available through the FAA
Regional Engineering Offices. In this connec-
tion, the flow rates and distribution of extin-
guishing agent substantiated in American
Airmotive Report No. 128–52–d, FAA ap-
proved February 9, 1953, provides protection
equivalent to that demonstrated by the CAA
in the CW–20 tests. In evaluating any C–46
fire-extinguishing system with respect to the
aforementioned CW–20 tests, the Administra-
tion would require data in a narrative form,
utilizing drawings or photographs to show at
least the following:
Installation of containers; installation and
routing of plumbing; type, number, and loca-
tion of outlets or nozzles; type, total volume,
and distribution of extinguishing agent;
length of time required for discharging;
means for thermal relief, including type and
location of discharge indicators; means of
discharging, e.g., mechanical cutterheads,
electric cartridge, or other method; and
whether a one- or two-shot system is used;
and if the latter is used, means of cross-feed-
ing or otherwise selecting distribution of ex-
tinguishing agent; and types of materials
used in makeup of plumbing.
High rate discharge (HRD) systems using
agents such as bromotrifluoromethane,
dibrodifluoromethane and
chlorobromomethane (CB), may also meet
the requirements of paragraph (a).
26.
Fire-extinguishing agents, Extinguishing
agent container pressure relief, Extinguishing
agent container compartment temperatures, and
Fire-extinguishing system materials.
No change
from the requirements of §§ 121.265 through
121.271.
27.
Fire-detector system.
Compliance with
the requirements of § 121.273 requires that C–
46 fire detector systems conform to:
(a) AD–62–10–2 or FAA approved equivalent
for engine compartments; and
(b) AD–49–18–1 or FAA approved equivalent
for combustion heater compartments
28.
Fire detectors.
No change from the re-
quirements of § 121.275.
29.
Protection of other airplane components
against fire.
To meet the requirements of
§ 121.277, C–46 airplanes must—
(a) Conform to the type design and all ap-
plicable airworthiness directives; and
(b) Be modified or have operational proce-
dures established to provide additional fire
protection for the wheel well door aft of each
engine compartment. Modifications may
consist of improvements in sealing of the
main landing gear wheel well doors. An oper-
ational procedure which is acceptable to the
Agency is one requiring the landing gear
control to be placed in the up position in
case of in-flight engine fire. In accordance
with § 121.315, such procedure must be set
forth in the emergency portion of the opera-
tor’s emergency checklist pertaining to in-
flight engine fire.
30.
Control of engine rotation.
C–46 propeller
feathering systems which conform to the
type design and all applicable airworthiness
directives meet the requirements of § 121.279.
31.
Fuel system independence.
C–46 fuel sys-
tems which conform to the type design and
all applicable airworthiness directives meet
the requirements of § 121.281.
32.
Induction system ice prevention.
The C–46
carburetor anti-icing system which conforms
to the type design and all applicable air-
worthiness directives meets the require-
ments of § 121.283.
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