title-14-part-29-sec29-1337

660

14 CFR Ch. I (1–1–24 Edition)

§ 29.1331

event of a malfunction, assuming that
corrective action begins within a rea-
sonable period of time.

(e) If the automatic pilot and flight

guidance system integrates signals
from auxiliary controls or furnishes
signals for operation of other equip-
ment, there must be a means to pre-
vent improper operation.

(f) If the automatic pilot system can

be coupled to airborne navigation
equipment, means must be provided to
indicate to the pilots the current mode
of operation. Selector switch position
is not acceptable as a means of indica-
tion.

[Doc. No. 5084, 29 FR 16150, Dec. 3, 1964, as
amended by Amdt. 29–24, 49 FR 44439, Nov. 6,
1984; Amdt. 29–24, 49 FR 47594, Dec. 6, 1984;
Amdt. 29–42, 63 FR 43285, Aug. 12, 1998; Amdt.
29–59, 88 FR 8739, Feb. 10, 2023]

§ 29.1331

Instruments using a power

supply.

For category A rotorcraft—
(a) Each required flight instrument

using a power supply must have—

(1) Two independent sources of power;
(2) A means of selecting either power

source; and

(3) A visual means integral with each

instrument to indicate when the power
adequate to sustain proper instrument
performance is not being supplied. The
power must be measured at or near the
point where it enters the instrument.
For electrical instruments, the power
is considered to be adequate when the
voltage is within the approved limits;
and

(b) The installation and power supply

system must be such that failure of
any flight instrument connected to one
source, or of the energy supply from
one source, or a fault in any part of the
power distribution system does not
interfere with the proper supply of en-
ergy from any other source.

[Doc. No. 5084, 29 FR 16150, Dec. 3, 1964, as
amended by Amdt. 29–24, 49 FR 44439, Nov. 6,
1984]

§ 29.1333

Instrument systems.

For systems that operate the re-

quired flight instruments which are lo-
cated at each pilot’s station, the fol-
lowing apply:

(a) For pneumatic systems, only the

required flight instruments for the

first pilot may be connected to that op-
erating system.

(b) The equipment, systems, and in-

stallations must be designed so that
one display of the information essen-
tial to the safety of flight which is pro-
vided by the flight instruments re-
mains available to a pilot, without ad-
ditional crewmember action, after any
single failure or combination of fail-
ures that are not shown to be ex-
tremely improbable.

or equipment may not be connected to
the operating system for a second pilot
unless provisions are made to ensure
the continued normal functioning of
the required flight instruments in the
event of any malfunction of the addi-
tional instruments, systems, or equip-
ment which is not shown to be ex-
tremely improbable.

[Amdt. 29–24, 49 FR 44439, Nov. 6, 1984, as
amended by Amdt. 29–59, 88 FR 8740, Feb. 10,
2023]

§ 29.1337

Powerplant instruments.

(a)

Instruments and instrument lines.

(1) Each powerplant and auxiliary
power unit instrument line must meet
the requirements of §§ 29.993 and 29.1183.

(2) Each line carrying flammable

fluids under pressure must—

(i) Have restricting orifices or other

safety devices at the source of pressure
to prevent the escape of excessive fluid
if the line fails; and

(ii) Be installed and located so that

the escape of fluids would not create a
hazard.

(3) Each powerplant and auxiliary

power unit instrument that utilizes
flammable fluids must be installed and
located so that the escape of fluid
would not create a hazard.

(b)

Fuel quantity indicator. There

must be means to indicate to the flight
crew members the quantity, in gallons
or equivalent units, of usable fuel in
each tank during flight. In addition—

(1) Each fuel quantity indicator must

be calibrated to read ‘‘zero’’ during
level flight when the quantity of fuel
remaining in the tank is equal to the
unusable fuel supply determined under
§ 29.959;

VerDate Sep<11>2014

09:06 Jun 28, 2024

Jkt 262046

PO 00000

Frm 00670

Fmt 8010

Sfmt 8010

Y:\SGML\262046.XXX

262046

jspears on DSK121TN23PROD with CFR

661

Federal Aviation Administration, DOT

§ 29.1351

(2) When two or more tanks are close-

ly interconnected by a gravity feed sys-
tem and vented, and when it is impos-
sible to feed from each tank sepa-
rately, at least one fuel quantity indi-
cator must be installed;

(3) Tanks with interconnected outlets

and airspaces may be treated as one
tank and need not have separate indi-
cators; and

(4) Each exposed sight gauge used as

a fuel quantity indicator must be pro-
tected against damage.

(c)

Fuel flowmeter system. If a fuel

flowmeter system is installed, each
metering component must have a
means for bypassing the fuel supply if
malfunction of that component se-
verely restricts fuel flow.

(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—