591 

Federal Aviation Administration, DOT 

§ 29.497 

(4) If there are two wheels forward, a 

distribution of the loads applied to 
those wheels under paragraphs (b)(1) 
and (2) of this section in a ratio of 
40:60. 

(c) 

Pitching moments. 

Pitching mo-

ments are assumed to be resisted by— 

(1) In the case of the attitude in para-

graph (a)(1) of this section, the forward 
landing gear; and 

(2) In the case of the attitude in para-

graph (a)(2) of this section, the angular 
inertia forces. 

§ 29.481

Tail-down landing conditions. 

(a) The rotorcraft is assumed to be in 

the maximum nose-up attitude allow-
ing ground clearance by each part of 
the rotorcraft. 

(b) In this attitude, ground loads are 

assumed to act perpendicular to the 
ground. 

§ 29.483

One-wheel landing conditions. 

For the one-wheel landing condition, 

the rotorcraft is assumed to be in the 
level attitude and to contact the 
ground on one aft wheel. In this atti-
tude— 

(a) The vertical load must be the 

same as that obtained on that side 
under § 29.479(b)(1); and 

(b) The unbalanced external loads 

must be reacted by rotorcraft inertia. 

§ 29.485

Lateral drift landing condi-

tions. 

(a) The rotorcraft is assumed to be in 

the level landing attitude, with— 

(1) Side loads combined with one-half 

of the maximum ground reactions ob-
tained in the level landing conditions 
of § 29.479(b)(1); and 

(2) The loads obtained under para-

graph (a)(1) of this section applied— 

(i) At the ground contact point; or 
(ii) For full-swiveling gear, at the 

center of the axle. 

(b) The rotorcraft must be designed 

to withstand, at ground contact— 

(1) When only the aft wheels contact 

the ground, side loads of 0.8 times the 
vertical reaction acting inward on one 
side and 0.6 times the vertical reaction 
acting outward on the other side, all 
combined with the vertical loads speci-
fied in paragraph (a) of this section; 
and 

(2) When the wheels contact the 

ground simultaneously— 

(i) For the aft wheels, the side loads 

specified in paragraph (b)(1) of this sec-
tion; and 

(ii) For the forward wheels, a side 

load of 0.8 times the vertical reaction 
combined with the vertical load speci-
fied in paragraph (a) of this section. 

§ 29.493

Braked roll conditions. 

Under braked roll conditions with 

the shock absorbers in their static po-
sitions— 

(a) The limit vertical load must be 

based on a load factor of at least— 

(1) 1.33, for the attitude specified in 

§ 29.479(a)(1); and 

(2) 1.0, for the attitude specified in 

§ 29.479(a)(2); and 

(b) The structure must be designed to 

withstand, at the ground contact point 
of each wheel with brakes, a drag load 
of at least the lesser of— 

(1) The vertical load multiplied by a 

coefficient of friction of 0.8; and 

(2) The maximum value based on lim-

iting brake torque. 

§ 29.497

Ground loading conditions: 

landing gear with tail wheels. 

(a) 

General. 

Rotorcraft with landing 

gear with two wheels forward and one 
wheel aft of the center of gravity must 
be designed for loading conditions as 
prescribed in this section. 

(b) 

Level landing attitude with only the 

forward wheels contacting the ground. 

In 

this attitude— 

(1) The vertical loads must be applied 

under §§ 29.471 through 29.475; 

(2) The vertical load at each axle 

must be combined with a drag load at 
that axle of not less than 25 percent of 
that vertical load; and 

(3) Unbalanced pitching moments are 

assumed to be resisted by angular iner-
tia forces. 

(c) 

Level landing attitude with all 

wheels contacting the ground simulta-
neously. 

In this attitude, the rotorcraft 

must be designed for landing loading 
conditions as prescribed in paragraph 
(b) of this section. 

(d) 

Maximum nose-up attitude with 

only the rear wheel contacting the 
ground. 

The attitude for this condition 

must be the maximum nose-up attitude 

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