spaschal on DSK3GDR082PROD with CFR

Federal Aviation Administration, DOT

Section 29.1353

and do not cause a smoke or fire hazard;
(5) There are means accessible in
flight to appropriate crewmembers for
the individual and collective disconnection of the electrical power
sources from the main bus; and
(6) There are means to indicate to appropriate crewmembers the generating
system quantities essential for the safe
operation of the system, such as the
voltage and current supplied by each
generator.
(c) External power. If provisions are
made for connecting external power to
the rotorcraft, and that external power
can be electrically connected to equipment 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 rotorcraft-s electrical system.
(d) Operation with the normal electrical power generating system inoperative.
(1) It must be shown by analysis,
tests, or both, that the rotorcraft can
be operated safely in VFR conditions
for a period of not less than 5 minutes,
with the normal electrical power generating
system
(electrical
power
sources excluding the battery) inoperative, with critical type fuel (from the
standpoint of flameout and restart capability), and with the rotorcraft initially at the maximum certificated altitude. Parts of the electrical system
may remain on if - 
(i) A single malfunction, including a
wire bundle or junction box fire, cannot result in loss of the part turned off
and the part turned on;
(ii) The parts turned on are electrically and mechanically isolated
from the parts turned off; and
(2) Additional requirements for Category A Rotorcraft.
(i) Unless it can be shown that the
loss of the normal electrical power generating system is extremely improbable, an emergency electrical power
system, independent of the normal
electrical power generating system,
must be provided, with sufficient capacity to power all systems necessary
for continued safe flight and landing.
(ii) Failures, including junction box,
control panel, or wire bundle fires,

which would result in the loss of the
normal and emergency systems, must
be shown to be extremely improbable.
(iii) Systems necessary for immediate safety must continue to operate
following the loss of the normal electrical power generating system, without the need for flight crew action.
(Secs. 313(a), 601, 603, 604, and 605 of the Federal Aviation Act of 1958 (49 U.S.C. 1354(a),
1421, 1423, 1424, and 1425); and 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. 29-14, 42 FR 36973, July 18,
1977; Amdt. 29-40, 61 FR 21908, May 10, 1996;
Amdt. 29-42, 63 FR 43285, Aug. 12, 1998]

Section 29.1353 Electrical equipment and installations.
(a) Electrical equipment, controls,
and wiring must be installed so that
operation of any one unit or system of
units will not adversely affect the simultaneous operation of any other
electrical unit or system essential to
safe operation.
(b) Cables must be grouped, routed,
and spaced so that damage to essential
circuits will be minimized if there are
faults in heavy current-carrying cables.
(c) Storage batteries must be designed and installed as follows:
(1) Safe cell temperatures and pressures must be maintained during any
probable charging and discharging condition. No uncontrolled increase in cell
temperature may result when the battery is recharged (after previous complete discharge) - 
(i) At maximum regulated voltage or
power;
(ii) During a flight of maximum duration; and
(iii) Under the most adverse cooling
condition likely in service.
(2) Compliance with paragraph (a)(1)
of this section must be shown by test
unless experience with similar batteries and installations has shown that
maintaining safe cell temperatures and
pressures presents no problem.
(3) No explosive or toxic gases emitted by any battery in normal operation, or as the result of any probable
malfunction in the charging system or
battery installation, may accumulate
in hazardous quantities within the
rotorcraft.

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