Section 29.1325

14 CFR Ch. I (1-1-19 Edition)

(c) For Category A rotorcraft - 
(1) The indication must allow consistent definition of the takeoff decision point; and
(2) The system error, excluding the
airspeed instrument calibration error,
may not exceed - 
(i) Three percent or 5 knots, whichever is greater, in level flight at speeds
above 80 percent of takeoff safety
speed; and
(ii) Ten knots in climb at speeds from
10 knots below takeoff safety speed to
10 knots above VY.
(d) For Category B rotorcraft, the
system error, excluding the airspeed
instrument calibration error, may not
exceed 3 percent or 5 knots, whichever
is greater, in level flight at speeds
above 80 percent of the climbout speed
attained at 50 feet when complying
with Section 29.63.
(e) Each system must be arranged, so
far as practicable, to prevent malfunction or serious error due to the entry of
moisture, dirt, or other substances.
(f) Each system must have a heated
pitot tube or an equivalent means of
preventing malfunction due to icing.

spaschal on DSK3GDR082PROD with CFR

[Doc. No. 5084, 29 FR 16150, Dec. 3, 1964, as
amended by Amdt. 29-3, 33 FR 970, Jan. 26,
1968; Amdt. 29-24, 49 FR 44439, Nov. 6, 1984;
Amdt. 29-39, 61 FR 21901, May 10, 1996; Amdt.
29-44, 64 FR 45338, Aug. 19, 1999]

Section 29.1325 Static pressure and pressure
altimeter systems.
(a) Each instrument with static air
case connections must be vented to the
outside atmosphere through an appropriate piping system.
(b) Each vent must be located where
its orifices are least affected by airflow
variation, moisture, or foreign matter.
(c) Each static pressure port must be
designed and located in such manner
that the correlation between air pressure in the static pressure system and
true ambient atmospheric static pressure is not altered when the rotorcraft
encounters icing conditions. An antiicing 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 atmosphere, each system must be airtight.
(e) Each pressure altimeter must be
approved and calibrated to indicate
pressure altitude in a standard atmosphere with a minimum practicable
calibration error when the corresponding 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 instrument calibration error, does not result
in an error of more than Section30 feet per 100
knots speed. However, the error need
not be less than Section30 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 Federal 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]

Section 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.

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