588 

14 CFR Ch. I (1–1–19 Edition) 

§ 29.341 

µ =

V cos a

R

Ω

where— 

V 

= The airspeed along the flight path 

(f.p.s.); 

a 

= The angle between the projection, in the 

plane of symmetry, of the axis of no 
feathering and a line perpendicular to 
the flight path (radians, positive when 
axis is pointing aft); 

W 

= The angular velocity of rotor (radians 

per second); and 

R 

= The rotor radius (ft.). 

§ 29.341

Gust loads. 

Each rotorcraft must be designed to 

withstand, at each critical airspeed in-
cluding hovering, the loads resulting 
from vertical and horizontal gusts of 30 
feet per second. 

§ 29.351

Yawing conditions. 

(a) Each rotorcraft must be designed 

for the loads resulting from the maneu-
vers specified in paragraphs (b) and (c) 
of this section, with— 

(1) Unbalanced aerodynamic mo-

ments about the center of gravity 
which the aircraft reacts to in a ration-
al or conservative manner considering 
the principal masses furnishing the re-
acting inertia forces; and 

(2) Maximum main rotor speed. 
(b) To produce the load required in 

paragraph (a) of this section, in unac-
celerated flight with zero yaw, at for-
ward speeds from zero up to 0.6 V

NE

— 

(1) Displace the cockpit directional 

control suddenly to the maximum de-
flection limited by the control stops or 
by the maximum pilot force specified 
in § 29.397(a); 

(2) Attain a resulting sideslip angle 

or 90

°

, whichever is less; and 

(3) Return the directional control 

suddenly to neutral. 

(c) To produce the load required in 

paragraph (a) of the section, in unac-
celerated flight with zero yaw, at for-
ward speeds from 0.6 V

NE

up to V

NE

or 

V

H

, whichever is less— 

(1) Displace the cockpit directional 

control suddenly to the maximum de-
flection limited by the control stops or 
by the maximum pilot force specified 
in § 29.397(a); 

(2) Attain a resulting sideslip angle 

or 15

°

, whichever is less, at the lesser 

speed of V

NE

or V

H

; 

(3) Vary the sideslip angles of para-

graphs (b)(2) and (c)(2) of this section 
directly with speed; and 

(4) Return the directional control 

suddenly to neutral. 

[Amdt. 29–26, 55 FR 8002, Mar. 6, 1990, as 
amended by Amdt. 29–41, 62 FR 46173, Aug. 29, 
1997] 

§ 29.361

Engine torque. 

The limit engine torque may not be 

less than the following: 

(a) For turbine engines, the highest 

of— 

(1) The mean torque for maximum 

continuous power multiplied by 1.25; 

(2) The torque required by § 29.923; 
(3) The torque required by § 29.927; or 
(4) The torque imposed by sudden en-

gine stoppage due to malfunction or 
structural failure (such as compressor 
jamming). 

(b) For reciprocating engines, the 

mean torque for maximum continuous 
power multiplied by— 

(1) 1.33, for engines with five or more 

cylinders; and 

(2) Two, three, and four, for engines 

with four, three, and two cylinders, re-
spectively. 

[Amdt. 29–26, 53 FR 34215, Sept. 2, 1988] 

C

ONTROL

S

URFACE AND

S

YSTEM

L

OADS

 

§ 29.391

General. 

Each auxiliary rotor, each fixed or 

movable stabilizing or control surface, 
and each system operating any flight 
control must meet the requirements of 
§§ 29.395 through 29.399, 29.411, and 
29.427. 

[Amdt. 29–26, 55 FR 8002, Mar. 6, 1990, as 
amended by Amdt. 29–41, 62 FR 46173, Aug. 29, 
1997] 

§ 29.395

Control system. 

(a) The reaction to the loads pre-

scribed in § 29.397 must be provided by— 

(1) The control stops only; 
(2) The control locks only; 
(3) The irreversible mechanism only 

(with the mechanism locked and with 
the control surface in the critical posi-
tions for the effective parts of the sys-
tem within its limit of motion); 

(4) The attachment of the control 

system to the rotor blade pitch control 

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