title-14-part-27-sec27-1357

552

14 CFR Ch. I (1–1–24 Edition)

§ 27.1353

(4) Each electric power source control

must allow the independent operation
of each source.

(c)

Generating system. There must be

at least one generator if the system
supplies power to load circuits essen-
tial for safe operation. In addition—

(1) Each generator must be able to

deliver its continuous rated power;

(2) Generator voltage control equip-

ment must be able to dependably regu-
late each generator output within
rated limits;

(3) Each generator must have a re-

verse current cutout designed to dis-
connect the generator from the battery
and from the other generators when
enough reverse current exists to dam-
age that generator; and

(4) Each generator must have an

overvoltage control designed and in-
stalled to prevent damage to the elec-
trical system, or to equipment supplied
by the electrical system, that could re-
sult if that generator were to develop
an overvoltage condition.

(d)

Instruments. There must be means

to indicate to appropriate crew-
members the electric power system
quantities essential for safe operation
of the system. In addition—

(1) For direct current systems, an

ammeter that can be switched into
each generator feeder may be used; and

(2) If there is only one generator, the

ammeter may be in the battery feeder.

(e)

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.

(Secs. 313(a), 601, 603, 604, and 605 of the Fed-
eral Aviation Act of 1958 (49 U.S.C. 1354(a),
1421, 1423, 1424, and 1425); and sec. 6(c) of the
Dept. of Transportation Act (49 U.S.C.
1655(c)))

[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964, as
amended by Amdt. 27–11, 41 FR 55470, Dec. 20,
1976; Amdt. 27–13, 42 FR 36972, July 18, 1977]

§ 27.1353

Energy storage systems.

Energy storage systems must be de-

signed and installed as follows:

(a) Energy storage systems must pro-

vide automatic protective features for
any conditions that could prevent con-
tinued safe flight and landing.

(b) Energy storage systems must not

emit any flammable, explosive, or
toxic gases, smoke, or fluids that could
accumulate in hazardous quantities
within the rotorcraft.

cape from the system must not damage
surrounding structures, adjacent equip-
ment, or systems necessary for contin-
ued safe flight and landing.

(d) The maximum amount of heat

and pressure that can be generated dur-
ing any operation or under any failure
condition of the energy storage system
or its individual components must not
result in any hazardous effect on rotor-
craft structure, equipment, or systems
necessary for continued safe flight and
landing.

(e) Energy storage system installa-

tions required for continued safe flight
and landing of the rotorcraft must
have monitoring features and a means
to indicate to the pilot the status of all
critical system parameters.

[Amdt. 27–51, 88 FR 8738, Feb. 10, 2023]

§ 27.1357

Circuit protective devices.

(a) Protective devices, such as fuses

or circuit breakers, must be installed
in each electrical circuit other than—

(1) The main circuits of starter mo-

tors; and

(2) Circuits in which no hazard is pre-

sented by their omission.

(b) A protective device for a circuit

essential to flight safety may not be
used to protect any other circuit.

device (‘‘trip free’’ device in which the
tripping mechanism cannot be over-
ridden by the operating control) must
be designed so that—

(1) A manual operation is required to

restore service after trippling; and

(2) If an overload or circuit fault ex-

ists, the device will open the circuit re-
gardless of the position of the oper-
ating control.

(d) If the ability to reset a circuit

breaker or replace a fuse is essential to
safety in flight, that circuit breaker or
fuse must be located and identified so
that it can be readily reset or replaced
in flight.

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§ 27.1385

(e) If fuses are used, there must be

one spare of each rating, or 50 percent
spare fuses of each rating, whichever is
greater.

(Secs. 313(a), 601, 603, 604, and 605 of the Fed-
eral Aviation Act of 1958 (49 U.S.C. 1354(a),
1421, 1423, 1424, and 1425); and sec. 6(c) of the
Dept. of Transportation Act (49 U.S.C.
1655(c)))

[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964; 29
FR 17885, Dec. 17, 1964, as amended by Amdt.
27–13, 42 FR 36972, July 18, 1977]

§ 27.1361

Master switch.

(a) There must be a master switch ar-

rangement to allow ready disconnec-
tion of each electric power source from
the main bus. The point of disconnec-
tion must be adjacent to the sources
controlled by the switch.

(b) Load circuits may be connected so

that they remain energized after the
switch is opened, if they are protected
by circuit protective devices, rated at
five amperes or less, adjacent to the
electric power source.

must be installed so that the switch is
easily discernible and accessible to a
crewmember in flight.

§ 27.1365

Electric cables.

(a) Each electric connecting cable

must be of adequate capacity.

(b) Each cable that would overheat in

the event of circuit overload or fault
must be at least flame resistant and
may not emit dangerous quantities of
toxic fumes.

cable installed in the rotorcraft must
be self-extinguishing when tested in ac-
cordance with appendix F, part I(a)(3),
of part 25 of this chapter.

[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964, as
amended by Amdt. 27–35, 63 FR 43285, Aug. 12,
1998]

§ 27.1367

Switches.

Each switch must be—
(a) Able to carry its rated current;
(b) Accessible to the crew; and
(c) Labeled as to operation and the

circuit controlled.

IGHTS

§ 27.1381

Instrument lights.

The instrument lights must—

(a) Make each instrument, switch,

and other devices for which they are
provided easily readable; and

(b) Be installed so that—
(1) Their direct rays are shielded

from the pilot’s eyes; and

(2) No objectionable reflections are

visible to the pilot.

§ 27.1383

Landing lights.

(a) Each required landing or hovering

light must be approved.

(b) Each landing light must be in-

stalled so that—

(1) No objectionable glare is visible

to the pilot;

(2) The pilot is not adversely affected

by halation; and

(3) It provides enough light for night

operation, including hovering and land-
ing.

be provided, as applicable—

(1) For each separately installed

landing light; and

(2) For each group of landing lights

installed at a common location.

§ 27.1385

Position light system installa-

tion.

(a)

General. Each part of each posi-

tion light system must meet the appli-
cable requirements of this section, and
each system as a whole must meet the
requirements of §§ 27.1387 through
27.1397.

(b)

Forward position lights. Forward

position lights must consist of a red
and a green light spaced laterally as
far apart as practicable and installed
forward on the rotorcraft so that, with
the rotorcraft in the normal flying po-
sition, the red light is on the left side
and the green light is on the right side.
Each light must be approved.

(c)

Rear position light. The rear posi-

tion light must be a white light mount-
ed as far aft as practicable, and must
be approved.

(d)

Circuit. The two forward position

lights and the rear position light must
make a single circuit.

(e)

Light covers and color filters. Each

light cover or color filter must be at
least flame resistant and may not
change color or shape or lose any ap-
preciable light transmission during
normal use.