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14 CFR Ch. I (1–1–19 Edition) 

§ 29.501 

expected in normal operation, includ-
ing autorotative landings. In this atti-

(1) The appropriate ground loads 

specified in paragraph (b)(1) and (2) of 
this section must be determined and 
applied, using a rational method to ac-
count for the moment arm between the 
rear wheel ground reaction and the 
rotorcraft center of gravity; or 

(2) The probability of landing with 

initial contact on the rear wheel must 
be shown to be extremely remote. 


Level landing attitude with only one 

forward wheel contacting the ground. 


this attitude, the rotorcraft must be 
designed for ground loads as specified 
in paragraph (b)(1) and (3) of this sec-


Side loads in the level landing atti-


In the attitudes specified in para-

graphs (b) and (c) of this section, the 
following apply: 

(1) The side loads must be combined 

at each wheel with one-half of the max-
imum vertical ground reactions ob-
tained for that wheel under paragraphs 
(b) and (c) of this section. In this condi-
tion, the side loads must be— 

(i) For the forward wheels, 0.8 times 

the vertical reaction (on one side) act-
ing inward, and 0.6 times the vertical 
reaction (on the other side) acting out-
ward; and 

(ii) For the rear wheel, 0.8 times the 

vertical reaction. 

(2) The loads specified in paragraph 

(f)(1) of this section must be applied— 

(i) At the ground contact point with 

the wheel in the trailing position (for 
non-full swiveling landing gear or for 
full swiveling landing gear with a lock, 
steering device, or shimmy damper to 
keep the wheel in the trailing posi-
tion); or 

(ii) At the center of the axle (for full 

swiveling landing gear without a lock, 
steering device, or shimmy damper). 


Braked roll conditions in the level 

landing attitude. 

In the attitudes speci-

fied in paragraphs (b) and (c) of this 
section, and with the shock absorbers 
in their static positions, the rotorcraft 
must be designed for braked roll loads 
as follows: 

(1) The limit vertical load must be 

based on a limit vertical load factor of 
not less than— 

(i) 1.0, for the attitude specified in 

paragraph (b) of this section; and 

(ii) 1.33, for the attitude specified in 

paragraph (c) of this section. 

(2) For each wheel with brakes, a 

drag load must be applied, at the 
ground contact point, of not less than 
the lesser of— 

(i) 0.8 times the vertical load; and 
(ii) The maximum based on limiting 

brake torque. 


Rear wheel turning loads in the 

static ground attitude. 

In the static 

ground attitude, and with the shock 
absorbers and tires in their static posi-
tions, the rotorcraft must be designed 
for rear wheel turning loads as follows: 

(1) A vertical ground reaction equal 

to the static load on the rear wheel 
must be combined with an equal side 

(2) The load specified in paragraph 

(h)(1) of this section must be applied to 
the rear landing gear— 

(i) Through the axle, if there is a 

swivel (the rear wheel being assumed 
to be swiveled 90 degrees to the longi-
tudinal axis of the rotorcraft); or 

(ii) At the ground contact point if 

there is a lock, steering device or shim-
my damper (the rear wheel being as-
sumed to be in the trailing position). 


Taxiing condition. 

The rotorcraft 

and its landing gear must be designed 
for the loads that would occur when 
the rotorcraft is taxied over the rough-
est ground that may reasonably be ex-
pected in normal operation. 

§ 29.501

Ground loading conditions: 

landing gear with skids. 



Rotorcraft with landing 

gear with skids must be designed for 
the loading conditions specified in this 
section. In showing compliance with 
this section, the following apply: 

(1) The design maximum weight, cen-

ter of gravity, and load factor must be 
determined under §§ 29.471 through 

(2) Structural yielding of elastic 

spring members under limit loads is ac-

(3) Design ultimate loads for elastic 

spring members need not exceed those 
obtained in a drop test of the gear 

(i) A drop height of 1.5 times that 

specified in § 29.725; and 

VerDate Sep<11>2014 

12:50 Apr 30, 2019

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