title-14-part-27-sec27-1317

548

14 CFR Ch. I (1–1–24 Edition)

§ 27.1316

event of a failure must be provided
when an unsafe system operating con-
dition exists and to enable them to
take corrective action. Systems, con-
trols, and associated monitoring and
crew alerting means must be designed
to minimize crew errors that could cre-
ate additional hazards.

(d) Compliance with the require-

ments of this section must be shown by
analysis and, where necessary, by
ground, flight, or simulator tests. The
analysis must account for:

(1) Possible modes of failure, includ-

ing malfunctions and misleading data
and input from external sources;

(2) The effect of multiple failures and

latent failures;

(3) The resulting effects on the rotor-

craft and occupants, considering the
stage of flight and operating condi-
tions; and

(4) The crew alerting cues and the

corrective action required.

[Amdt. 27–51, 88 FR 8737, Feb. 10, 2023]

§ 27.1316

Electrical and electronic sys-

tem lightning protection.

(a) Each electrical and electronic

system that performs a function, for
which failure would prevent the contin-
ued safe flight and landing of the rotor-
craft, must be designed and installed so
that—

(1) The function is not adversely af-

fected during and after the time the
rotorcraft is exposed to lightning; and

(2) The system automatically recov-

ers normal operation of that function
in a timely manner after the rotorcraft
is exposed to lightning.

(b) For rotorcraft approved for in-

strument flight rules operation, each
electrical and electronic system that
performs a function, for which failure
would reduce the capability of the
rotorcraft or the ability of the
flightcrew to respond to an adverse op-
erating condition, must be designed
and installed so that the function re-
covers normal operation in a timely
manner after the rotorcraft is exposed
to lightning.

[Doc. No. FAA–2010–0224, Amdt. 27–46, 76 FR
33135, June 8, 2011]

§ 27.1317

High-intensity Radiated

Fields (HIRF) Protection.

(a) Except as provided in paragraph

(d) of this section, each electrical and
electronic system that performs a func-
tion whose failure would prevent the
continued safe flight and landing of the
rotorcraft must be designed and in-
stalled so that—

(1) The function is not adversely af-

fected during and after the time the
rotorcraft is exposed to HIRF environ-
ment I, as described in appendix D to
this part;

(2) The system automatically recov-

ers normal operation of that function,
in a timely manner, after the rotor-
craft is exposed to HIRF environment
I, as described in appendix D to this
part, unless this conflicts with other
operational or functional requirements
of that system;

(3) The system is not adversely af-

fected during and after the time the
rotorcraft is exposed to HIRF environ-
ment II, as described in appendix D to
this part; and

(4) Each function required during op-

eration under visual flight rules is not
adversely affected during and after the
time the rotorcraft is exposed to HIRF
environment III, as described in appen-
dix D to this part.

(b) Each electrical and electronic

system that performs a function whose
failure would significantly reduce the
capability of the rotorcraft or the abil-
ity of the flightcrew to respond to an
adverse operating condition must be
designed and installed so the system is
not adversely affected when the equip-
ment providing these functions is ex-
posed to equipment HIRF test level 1
or 2, as described in appendix D to this
part.

tem that performs a function whose
failure would reduce the capability of
the rotorcraft or the ability of the
flightcrew to respond to an adverse op-
erating condition, must be designed
and installed so the system is not ad-
versely affected when the equipment
providing these functions is exposed to
equipment HIRF test level 3, as de-
scribed in appendix D to this part.

(d) Before December 1, 2012, an elec-

trical or electronic system that per-
forms a function whose failure would

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§ 27.1325

prevent the continued safe flight and
landing of a rotorcraft may be designed
and installed without meeting the pro-
visions of paragraph (a) provided—

(1) The system has previously been

shown to comply with special condi-
tions for HIRF, prescribed under § 21.16,
issued before December 1, 2007;

(2) The HIRF immunity characteris-

tics of the system have not changed
since compliance with the special con-
ditions was demonstrated; and

(3) The data used to demonstrate

compliance with the special conditions
is provided.

[Doc. No. FAA–2006–23657, 72 FR 44026, Aug. 6,
2007]

NSTRUMENTS

: I

NSTALLATION

§ 27.1321

Arrangement and visibility.

(a) Each flight, navigation, and pow-

erplant instrument for use by any pilot
must be easily visible to him.

(b) For each multiengine rotorcraft,

identical powerplant instruments must
be located so as to prevent confusion as
to which engine each instrument re-
lates.

not damage, or impair the readability
or accuracy of, any instrument.

(d) If a visual indicator is provided to

indicate malfunction of an instrument,
it must be effective under all probable
cockpit lighting conditions.

(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 36971, July 18, 1977]

§ 27.1322

Warning, caution, and advi-

sory lights.

If warning, caution or advisory lights

are installed in the cockpit, they must,
unless otherwise approved by the Ad-
ministrator, be—

(a) Red, for warning lights (lights in-

dicating a hazard which may require
immediate corrective action):

(b) Amber, for caution lights (lights

indicating the possible need for future
corrective action);

and

(d) Any other color, including white,

for lights not described in paragraphs
(a) through (c) of this section, provided
the color differs sufficiently from the
colors prescribed in paragraphs (a)
through (c) of this section to avoid pos-
sible confusion.

[Amdt. 27–11, 41 FR 55470, Dec. 20, 1976]

§ 27.1323

Airspeed indicating system.

(a) Each airspeed indicating instru-

ment must be calibrated to indicate
true airspeed (at sea level with a stand-
ard atmosphere) with a minimum prac-
ticable instrument calibration error
when the corresponding pitot and stat-
ic pressures are applied.

(b) The airspeed indicating system

must be calibrated in flight at forward
speeds of 20 knots and over.

percent of the climbout speed, the air-
speed indicator must indicate true air-
speed, at sea level with a standard at-
mosphere, to within an allowable in-
stallation error of not more than the
greater of—

(1)

3 percent of the calibrated air-

speed; or

(2) Five knots.

(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. 27–13, 42 FR 36972, July 18,
1977]

§ 27.1325

Static pressure systems.

(a) Each instrument with static air

case connections must be vented so
that the influence of rotorcraft speed,
the opening and closing of windows,
airflow variation, and moisture or
other foreign matter does not seriously
affect its accuracy.

(b) Each static pressure port must be

designed and located in such manner
that the correlation between air pres-
sure in the static pressure system and
true ambient atmospheric static pres-
sure is not altered when the rotorcraft
encounters icing conditions. An anti-
icing means or an alternate source of
static pressure may be used in showing
compliance with this requirement. If
the reading of the altimeter, when on