Pt. 29, App. B

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

a prominent location that reads:  - The Airworthiness Limitations section is FAA approved and specifies maintenance required
under SectionSection 43.16 and 91.403 of the Federal Aviation Regulations unless an alternative program has been FAA approved. - 
[Amdt. 29-20, 45 FR 60178, Sept. 11, 1980, as
amended by Amdt. 29-27, 54 FR 34330, Aug. 18,
1989; Amdt. 29-54, 76 FR 74664, Dec. 1, 2011]

spaschal on DSK3GDR082PROD with CFR

APPENDIX B TO PART 29 - AIRWORTHINESS CRITERIA FOR HELICOPTER INSTRUMENT FLIGHT
I. General. A transport category helicopter
may not be type certificated for operation
under the instrument flight rules (IFR) of
this chapter unless it meets the design and
installation requirements contained in this
appendix.
II. Definitions. (a) VYI means instrument
climb speed, utilized instead of VY for compliance with the climb requirements for instrument flight.
(b) VNEI means instrument flight never exceed speed, utilized instead of VNE for compliance with maximum limit speed requirements for instrument flight.
(c) VMINI means instrument flight minimum speed, utilized in complying with minimum limit speed requirements for instrument flight.
III. Trim. It must be possible to trim the
cyclic, collective, and directional control
forces to zero at all approved IFR airspeeds,
power settings, and configurations appropriate to the type.
IV. Static longitudinal stability. (a) General.
The helicopter must possess positive static
longitudinal control force stability at critical combinations of weight and center of
gravity at the conditions specified in paragraphs IV (b) through (f) of this appendix.
The stick force must vary with speed so that
any substantial speed change results in a
stick force clearly perceptible to the pilot.
The airspeed must return to within 10 percent of the trim speed when the control force
is slowly released for each trim condition
specified in paragraphs IV (b) through (f) of
this appendix.
(b) Climb. Stability must be shown in climb
thoughout the speed range 20 knots either
side of trim with - 
(1) The helicopter trimmed at VYI;
(2) Landing gear retracted (if retractable);
and
(3) Power required for limit climb rate (at
least 1,000 fpm) at VYI or maximum continuous power, whichever is less.
(c) Cruise. Stability must be shown
throughout the speed range from 0.7 to 1.1 VH
or VNEI, whichever is lower, not to exceed Section20
knots from trim with - 

(1) The helicopter trimmed and power adjusted for level flight at 0.9 VH or 0.9 VNEI,
whichever is lower; and
(2) Landing gear retracted (if retractable).
(d) Slow cruise. Stability must be shown
throughout the speed range from 0.9 VMINI to
1.3 VMINI or 20 knots above trim speed, whichever is greater, with - 
(1) The helicopter trimmed and power adjusted for level flight at 1.1 VMINI; and
(2) Landing gear retracted (if retractable).
(e) Descent. Stability must be shown
throughout the speed range 20 knots either
side of trim with - 
(1) The helicopter trimmed at 0.8 VH or 0.8
VNEI (or 0.8 VLE for the landing gear extended
case), whichever is lower;
(2) Power required for 1,000 fpm descent at
trim speed; and
(3) Landing gear extended and retracted, if
applicable.
(f) Approach. Stability must be shown
throughout the speed range from 0.7 times
the minimum recommended approach speed
to 20 knots above the maximum recommended approach speed with - 
(1) The helicopter trimmed at the recommended approach speed or speeds;
(2) Landing gear extended and retracted, if
applicable; and
(3) Power required to maintain a 3Section glide
path and power required to maintain the
steepest approach gradient for which approval is requested.
V. Static Lateral Directional Stability
(a) Static directional stability must be
positive throughout the approved ranges of
airspeed, power, and vertical speed. In
straight and steady sideslips up to Section10Section from
trim, directional control position must increase without discontinuity with the angle
of sideslip, except for a small range of sideslip angles around trim. At greater angles up
to the maximum sideslip angle appropriate
to the type, increased directional control position must produce an increased angle of
sideslip. It must be possible to maintain balanced flight without exceptional pilot skill
or alertness.
(b) During sideslips up to Section10Section from trim
throughout the approved ranges of airspeed,
power, and vertical speed there must be no
negative dihedral stability perceptible to the
pilot through lateral control motion or
force. Longitudinal cyclic movement with
sideslip must not be excessive.
VI. Dynamic stability. (a) Any oscillation
having a period of less than 5 seconds must
damp to 1-2 amplitude in not more than one
cycle.
(b) Any oscillation having a period of 5 seconds or more but less than 10 seconds must
damp to 1-2 amplitude in not more than two
cycles.
(c) Any oscillation having a period of 10
seconds or more but less than 20 seconds
must be damped.

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