title-14-part-29-sec29-1329

659

Federal Aviation Administration, DOT

§ 29.1329

outside atmosphere through an appro-
priate piping system.

(b) Each vent must be located where

its orifices are least affected by airflow
variation, moisture, or foreign matter.

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
the alternate static pressure system,
differs from the reading of altimeter
when on the primary static system by
more than 50 feet, a correction card
must be provided for the alternate
static system.

(d) Except for the vent into the at-

mosphere, each system must be air-
tight.

(e) Each pressure altimeter must be

approved and calibrated to indicate
pressure altitude in a standard atmos-
phere with a minimum practicable
calibration error when the cor-
responding static pressures are applied.

(f) Each system must be designed and

installed so that an error in indicated
pressure altitude, at sea level, with a
standard atmosphere, excluding instru-
ment calibration error, does not result
in an error of more than

30 feet per 100

knots speed. However, the error need
not be less than

30 feet.

(g) Except as provided in paragraph

(h) of this section, if the static pressure
system incorporates both a primary
and an alternate static pressure source,
the means for selecting one or the
other source must be designed so
that—

(1) When either source is selected, the

other is blocked off; and

(2) Both sources cannot be blocked

off simultaneously.

(h) For unpressurized rotorcraft,

paragraph (g)(1) of this section does not
apply if it can be demonstrated that
the static pressure system calibration,
when either static pressure source is
selected, is not changed by the other

static pressure source being open or
blocked.

(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), 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 36972, July 18,
1977; Amdt. 29–24, 49 FR 44439, Nov. 6, 1984]

§ 29.1327

Magnetic direction indicator.

(a) Each magnetic direction indicator

must be installed so that its accuracy
is not excessively affected by the
rotorcraft’s vibration or magnetic
fields.

(b) The compensated installation

may not have a deviation, in level
flight, greater than 10 degrees on any
heading.

§ 29.1329

Automatic pilot and flight

guidance system.

For the purpose of this subpart, an

automatic pilot and flight guidance
system may consist of an autopilot,
flight director, or a component that
interacts with stability augmentation
or trim.

(a) Each automatic pilot and flight

guidance system must be designed so
that it:

(1) Can be overpowered by one pilot

to allow control of the rotorcraft;

(2) Provides a means to disengage the

system, or any malfunctioning compo-
nent of the system, by each pilot to
prevent it from interfering with the
control of the rotorcraft; and

(3) Provides a means to indicate to

the flight crew its current mode of op-
eration. Selector switch position is not
acceptable as a means of indication.

(b) Unless there is automatic syn-

chronization, each system must have a
means to readily indicate to the pilot
the alignment of the actuating device
in relation to the control system it op-
erates.

for the system’s operation must be
readily accessible to the pilots.

(d) The system must be designed so

that, within the range of adjustment
available to the pilot, it cannot
produce hazardous loads on the rotor-
craft, or create hazardous deviations in
the flight path, under any flight condi-
tion appropriate to its use or in the

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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;