Section 29.629

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

(b) No fitting factor need be used - 
(1) For joints made under approved
practices and based on comprehensive
test data (such as continuous joints in
metal plating, welded joints, and scarf
joints in wood); and
(2) With respect to any bearing surface for which a larger special factor is
used.
(c) For each integral fitting, the part
must be treated as a fitting up to the
point at which the section properties
become typical of the member.
(d) Each seat, berth, litter, safety
belt, and harness attachment to the
structure must be shown by analysis,
tests, or both, to be able to withstand
the
inertia
forces
prescribed
in
Section 29.561(b)(3) multiplied by a fitting factor of 1.33.

(3) The blade must be designed to prevent water from becoming trapped in
it.
(b) Paragraphs (a)(1) and (2) of this
section does not apply to sealed rotor
blades capable of withstanding the
maximum pressure differentials expected in service.

[Doc. No. 5084, 29 FR 16150, Dec. 3, 1964, as
amended by Amdt. 29-42, 63 FR 43285, Aug. 12,
1998]

[Amdt. 29-3, 33 FR 967, Jan. 26, 1968]

Section 29.629 Flutter and divergence.
Each aerodynamic surface of the
rotorcraft must be free from flutter
and divergence under each appropriate
speed and power condition.

There must be enough clearance between the rotor blades and other parts
of the structure to prevent the blades
from striking any part of the structure
during any operating condition.

Section 29.659

Mass balance.

(a) The rotor and blades must be
mass balanced as necessary to - 
(1) Prevent excessive vibration; and
(2) Prevent flutter at any speed up to
the maximum forward speed.
(b) The structural integrity of the
mass balance installation must be substantiated.

Section 29.661

Rotor blade clearance.

[Amdt. 29-3, 33 FR 967, Jan. 26, 1968]

[Doc. No. 28008, 61 FR 21907, May 10, 1996]

Section 29.631 Bird strike.
The rotorcraft must be designed to
ensure capability of continued safe
flight and landing (for Category A) or
safe landing (for Category B) after impact with a 2.2-lb (1.0 kg) bird when the
velocity of the rotorcraft (relative to
the bird along the flight path of the
rotorcraft) is equal to VNE or VH
(whichever is the lesser) at altitudes up
to 8,000 feet. Compliance must be
shown by tests or by analysis based on
tests carried out on sufficiently representative structures of similar design.
[Doc. No. 28008, 61 FR 21907, May 10, 1996; 61
FR 33963, July 1, 1996]

ROTORS

spaschal on DSK3GDR082PROD with CFR

[Amdt. 29-3, 33 FR 967, Jan. 26, 1968]

Section 29.663 Ground resonance prevention
means.
(a) The reliability of the means for
preventing ground resonance must be
shown either by analysis and tests, or
reliable service experience, or by showing through analysis or tests that malfunction or failure of a single means
will not cause ground resonance.
(b) The probable range of variations,
during service, of the damping action
of the ground resonance prevention
means must be established and must be
investigated during the test required
by Section 29.241.
[Amdt. 27-26, 55 FR 8003, Mar. 6, 1990]

CONTROL SYSTEMS
Section 29.671

Section 29.653 Pressure venting and drainage of rotor blades.
(a) For each rotor blade - 
(1) There must be means for venting
the internal pressure of the blade;
(2) Drainage holes must be provided
for the blade; and

General.

(a) Each control and control system
must operate with the ease, smoothness, and positiveness appropriate to
its function.
(b) Each element of each flight control system must be designed, or distinctively and permanently marked, to

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