Code of Federal Regulations - Title 14

809

Federal Aviation Administration, DOT

§ 29.1351

(d)

Oil quantity indicator. There must

be a stick gauge or equivalent means
to indicate the quantity of oil—

(1) In each tank; and
(2) In each transmission gearbox.
(e) Rotor drive system transmissions

and gearboxes utilizing ferromagnetic
materials must be equipped with chip
detectors designed to indicate the pres-
ence of ferromagnetic particles result-
ing from damage or excessive wear
within the transmission or gearbox.
Each chip detector must—

(1) Be designed to provide a signal to

the indicator required by
§ 29.1305(a)(22); and

(2) Be provided with a means to allow

crewmembers to check, in flight, the
function of each detector electrical cir-
cuit and signal.

(Secs. 313(a), 601, and 603, 72 Stat. 759, 775, 49
U.S.C. 1354(a), 1421, and 1423; sec. 6(c), 49
U.S.C. 1655(c))

[Doc. No. 5084, 29 FR 16150, Dec. 3, 1964, as
amended by Amdt. 29–13, 42 FR 15047, Mar. 17,
1977; Amdt. 29–26, 53 FR 34219, Sept. 2, 1988]

LECTRICAL

YSTEMS AND

QUIPMENT

§ 29.1351

General.

(a)

Electrical system capacity. The re-

quired generating capacity and the
number and kind of power sources
must—

(1) Be determined by an electrical

load analysis; and

(2) Meet the requirements of § 29.1309.
(b)

Generating system. The generating

system includes electrical power
sources, main power busses, trans-
mission cables, and associated control,
regulation, and protective devices. It
must be designed so that—

(1) Power sources function properly

when independent and when connected
in combination;

(2) No failure or malfunction of any

power source can create a hazard or
impair the ability of remaining sources
to supply essential loads;

(3) The system voltage and frequency

(as applicable) at the terminals of es-
sential load equipment can be main-
tained within the limits for which the
equipment is designed, during any
probable operating condition;

(4) System transients due to switch-

ing, fault clearing, or other causes do
not make essential loads inoperative,

and do not cause a smoke or fire haz-
ard;

(5) There are means accessible in

flight to appropriate crewmembers for
the individual and collective dis-
connection of the electrical power
sources from the main bus; and

(6) There are means to indicate to ap-

propriate 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 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 rotorcraft’s electrical system.

(d) Operation with the normal elec-

trical power generating system inoper-
ative.

(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 gen-
erating system (electrical power
sources excluding the battery) inoper-
ative, with critical type fuel (from the
standpoint of flameout and restart ca-
pability), and with the rotorcraft ini-
tially at the maximum certificated al-
titude. Parts of the electrical system
may remain on if—

(i) 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;

(ii) The parts turned on are elec-

trically and mechanically isolated
from the parts turned off; and

(2) Additional requirements for Cat-

egory A Rotorcraft.

(i) Unless it can be shown that the

loss of the normal electrical power gen-
erating system is extremely improb-
able, an emergency electrical power
system, independent of the normal
electrical power generating system,
must be provided, with sufficient ca-
pacity to power all systems necessary
for continued safe flight and landing.

(ii) Failures, including junction box,

control panel, or wire bundle fires,

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