**Sec. 25.471 - General.**
(a) *Loads and equilibrium.* For
limit ground loads --

(1) Limit ground loads obtained under
this subpart are considered to be external forces applied to the airplane
structure; and

(2) In each specified ground load
condition, the external loads must be placed in equilibrium with the
linear and angular inertia loads in a rational or conservative manner.

(b) *Critical centers of gravity.*
The critical centers of gravity within the range for which certification
is requested must be selected so that the maximum design loads are
obtained in each landing gear element. Fore and aft, vertical, and lateral
airplane centers of gravity must be considered. Lateral displacements of
the c.g. from the airplane centerline which would result in main gear
loads not greater than 103 percent of the critical design load for
symmetrical loading conditions may be selected without considering the
effects of these lateral c.g. displacements on the loading of the main
gear elements, or on the airplane structure provided --

(1) The lateral displacement of the c.g.
results from random passenger or cargo disposition within the fuselage or
from random unsymmetrical fuel loading or fuel usage; and

(2) Appropriate loading instructions for
random disposable loads are included under the provisions of
§25.1583(c)(1) to ensure that the lateral displacement of the center of
gravity is maintained within these limits.

(c) *Landing gear dimension data.*
Figure 1 of appendix A contains the basic landing gear dimension data.