605
Federal Aviation Administration, DOT
§ 29.672
§ 29.561(b)(3) multiplied by a fitting fac-
tor of 1.33.
[Doc. No. 5084, 29 FR 16150, Dec. 3, 1964, as
amended by Amdt. 29–42, 63 FR 43285, Aug. 12,
1998]
§ 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.
[Doc. No. 28008, 61 FR 21907, May 10, 1996]
§ 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 im-
pact 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 V
NE
or V
H
(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 rep-
resentative structures of similar de-
sign.
[Doc. No. 28008, 61 FR 21907, May 10, 1996; 61
FR 33963, July 1, 1996]
R
OTORS
§ 29.653
Pressure venting and drain-
age 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
(3) The blade must be designed to pre-
vent 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 ex-
pected in service.
[Amdt. 29–3, 33 FR 967, Jan. 26, 1968]
§ 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 sub-
stantiated.
[Amdt. 29–3, 33 FR 967, Jan. 26, 1968]
§ 29.661
Rotor blade clearance.
There must be enough clearance be-
tween the rotor blades and other parts
of the structure to prevent the blades
from striking any part of the structure
during any operating condition.
[Amdt. 29–3, 33 FR 967, Jan. 26, 1968]
§ 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 show-
ing through analysis or tests that mal-
function 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 § 29.241.
[Amdt. 27–26, 55 FR 8003, Mar. 6, 1990]
C
ONTROL
S
YSTEMS
§ 29.671
General.
(a) Each control and control system
must operate with the ease, smooth-
ness, and positiveness appropriate to
its function.
(b) Each element of each flight con-
trol system must be designed, or dis-
tinctively and permanently marked, to
minimize the probability of any incor-
rect assembly that could result in the
malfunction of the system.
(c) A means must be provided to
allow full control movement of all pri-
mary flight controls prior to flight, or
a means must be provided that will
allow the pilot to determine that full
control authority is available prior to
flight.
[Doc. No. 5084, 29 FR 16150, Dec. 3, 1964, as
amended by Amdt. 29–24, 49 FR 44437, Nov. 6,
1984]
§ 29.672
Stability augmentation, auto-
matic, and power-operated systems.
If the functioning of stability aug-
mentation or other automatic or
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14 CFR Ch. I (1–1–24 Edition)
§ 29.673
power-operated system is necessary to
show compliance with the flight char-
acteristics requirements of this part,
the system must comply with § 29.671 of
this part and the following:
(a) A warning which is clearly distin-
guishable to the pilot under expected
flight conditions without requiring the
pilot’s attention must be provided for
any failure in the stability augmenta-
tion system or in any other automatic
or power-operated system which could
result in an unsafe condition if the
pilot is unaware of the failure. Warning
systems must not activate the control
systems.
(b) The design of the stability aug-
mentation system or of any other auto-
matic or power-operated system must
allow initial counteraction of failures
without requiring exceptional pilot
skill or strength, by overriding the
failure by moving the flight controls in
the normal sense, and by deactivating
the failed system.
(c) It must be show that after any
single failure of the stability aug-
mentation system or any other auto-
matic or power-operated system—
(1) The rotorcraft is safely control-
lable when the failure or malfunction
occurs at any speed or altitude within
the approved operating limitations;
(2) The controllability and maneuver-
ability requirements of this part are
met within a practical operational
flight envelope (for example, speed, al-
titude, normal acceleration, and rotor-
craft configurations) which is described
in the Rotorcraft Flight Manual; and
(3) The trim and stability character-
istics are not impaired below a level
needed to allow continued safe flight
and landing.
[Amdt. 29–24, 49 FR 44437, Nov. 6, 1984]
§ 29.673
Primary flight controls.
Primary flight controls are those
used by the pilot for immediate control
of pitch, roll, yaw, and vertical motion
of the rotorcraft.
[Amdt. 29–24, 49 FR 44437, Nov. 6, 1984]
§ 29.674
Interconnected controls.
Each primary flight control system
must provide for safe flight and landing
and operate independently after a mal-
function, failure, or jam of any auxil-
iary interconnected control.
[Amdt. 27–26, 55 FR 8003, Mar. 6, 1990]
§ 29.675
Stops.
(a) Each control system must have
stops that positively limit the range of
motionof the pilot’s controls.
(b) Each stop must be located in the
system so that the range of travel of
its control is not appreciably affected
by—
(1) Wear;
(2) Slackness; or
(3) Takeup adjustments.
(c) Each stop must be able to with-
stand the loads corresponding to the
design conditions for the system.
(d) For each main rotor blade—
(1) Stops that are appropriate to the
blade design must be provided to limit
travel of the blade about its hinge
points; and
(2) There must be means to keep the
blade from hitting the droop stops dur-
ing any operation other than starting
and stopping the rotor.
(Secs. 313(a), 601, 603, 604, Federal Aviation
Act of 1958 (49 U.S.C. 1354(a), 1421, 1423, 1424),
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. 29–17, 43 FR 50599, Oct. 30,
1978]
§ 29.679
Control system locks.
If there is a device to lock the con-
trol system with the rotorcraft on the
ground or water, there must be means
to—
(a) Automatically disengage the lock
when the pilot operates the controls in
a normal manner, or limit the oper-
ation of the rotorcraft so as to give un-
mistakable warning to the pilot before
takeoff; and
(b) Prevent the lock from engaging in
flight.
§ 29.681
Limit load static tests.
(a) Compliance with the limit load
requirements of this part must be
shown by tests in which—
(1) The direction of the test loads
produces the most severe loading in the
control system; and
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