807
Federal Aviation Administration, DOT
§ 29.1331
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 system.
(a) Each automatic pilot system
must be designed so that the automatic
pilot can—
(1) Be sufficiently overpowered by
one pilot to allow control of the rotor-
craft; and
(2) Be readily and positively dis-
engaged by each pilot to prevent it
from interfering with the control of the
rotorcraft.
(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.
(c) Each manually operated control
for the system’s operation must be
readily accessible to the pilots.
(d) The system must be designed and
adjusted so that, within the range of
adjustment available to the pilot, it
cannot produce hazardous loads on the
rotorcraft, or create hazardous devi-
ations in the flight path, under any
flight condition appropriate to its use,
either during normal operation or in
the event of a malfunction, assuming
that corrective action begins within a
reasonable period of time.
(e) If the automatic pilot integrates
signals from auxiliary controls or fur-
nishes signals for operation of other
equipment, there must be positive
interlocks and sequencing of engage-
ment to prevent 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]
§ 29.1331
Instruments using a power
supply.
For category A rotorcraft—
(a) Each required flight instrument
using a power supply must have—
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