307
Federal Aviation Administration, DOT
§ 23.1353
(v) For the purpose of complying
with paragraph (b)(5) of this section,
the distribution system includes the
distribution busses, their associated
feeders, and each control and protec-
tive device.
(c)
Generating system. There must be
at least one generator/alternator if the
electrical system supplies power to
load circuits essential for safe oper-
ation. In addition—
(1) Each generator/alternator must be
able to deliver its continuous rated
power, or such power as is limited by
its regulation system.
(2) Generator/alternator voltage con-
trol equipment must be able to depend-
ably regulate the generator/alternator
output within rated limits.
(3) Automatic means must be pro-
vided to prevent damage to any gener-
ator/alternator and adverse effects on
the airplane electrical system due to
reverse current. A means must also be
provided to disconnect each generator/
alternator from the battery and other
generators/alternators.
(4) There must be a means to give im-
mediate warning to the flight crew of a
failure of any generator/alternator.
(5) Each generator/alternator must
have an overvoltage control designed
and installed to prevent damage to the
electrical system, or to equipment sup-
plied by the electrical system that
could result if that generator/alter-
nator were to develop an overvoltage
condition.
(d)
Instruments. A means must exist
to indicate to appropriate flight crew-
members the electric power system
quantities essential for safe operation.
(1) For normal, utility, and acrobatic
category airplanes with direct current
systems, an ammeter that can be
switched into each generator feeder
may be used and, if only one generator
exists, the ammeter may be in the bat-
tery feeder.
(2) For commuter category airplanes,
the essential electric power system
quantities include the voltage and cur-
rent supplied by each generator.
(e)
Fire resistance. Electrical equip-
ment must be so designed and installed
that in the event of a fire in the engine
compartment, during which the surface
of the firewall adjacent to the fire is
heated to 2,000
°
F for 5 minutes or to a
lesser temperature substantiated by
the applicant, the equipment essential
to continued safe operation and located
behind the firewall will function satis-
factorily and will not create an addi-
tional fire hazard.
(f)
External power. If provisions are
made for connecting external power to
the airplane, and that external power
can be electrically connected to equip-
ment other than that used for engine
starting, means must be provided to
ensure that no external power supply
having a reverse polarity, or a reverse
phase sequence, can supply power to
the airplane’s electrical system. The
external power connection must be lo-
cated so that its use will not result in
a hazard to the airplane or ground per-
sonnel.
(g) It must be shown by analysis,
tests, or both, that the airplane can be
operated safely in VFR conditions, for
a period of not less than five minutes,
with the normal electrical power (elec-
trical power sources excluding the bat-
tery and any other standby electrical
sources) inoperative, with critical type
fuel (from the standpoint of flameout
and restart capability), and with the
airplane initially at the maximum cer-
tificated altitude. Parts of the elec-
trical system may remain on if—
(1) A single malfunction, including a
wire bundle or junction box fire, can-
not result in loss of the part turned off
and the part turned on; and
(2) The parts turned on are elec-
trically and mechanically isolated
from the parts turned off.
[Doc. No. 4080, 29 FR 17955, Dec. 18, 1964, as
amended by Amdt. 23–7, 34 FR 13096, Aug. 13,
1969; Amdt. 23–14, 38 FR 31824, Nov. 19, 1973;
Amdt. 23–17, 41 FR 55465, Dec. 20, 1976; Amdt.
23–20, 42 FR 36969, July 18, 1977; Amdt. 23–34,
52 FR 1834, Jan. 15, 1987; 52 FR 34745, Sept. 14,
1987; Amdt. 23–43, 58 FR 18976, Apr. 9, 1993;
Amdt. 23–49, 61 FR 5169, Feb. 9, 1996]
§ 23.1353
Storage battery design and
installation.
(a) Each storage battery must be de-
signed and installed as prescribed in
this section.
(b) Safe cell temperatures and pres-
sures must be maintained during any
probable charging and discharging con-
dition. No uncontrolled increase in cell
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