spaschal on DSK3GDR082PROD with CFR

Federal Aviation Administration, DOT

Section 25.735

The reactions in this case must be distributed to the nose and main wheels
by the principles of statics with a drag
reaction equal to 0.31 times the
vertical load at each wheel with brakes
capable of producing this ground reaction. This nose tire load may not exceed 1.5 times the load rating of the
tire.
(3) The ground reaction of the tire
corresponding to the most critical
combination of airplane weight (up to
maximum ramp weight) and center of
gravity position combined with forces
of 1.0g downward and 0.20g forward acting at the center of gravity. The reactions in this case must be distributed
to the nose and main wheels by the
principles of statics with a drag reaction equal to 0.20 times the vertical
load at each wheel with brakes capable
of producing this ground reaction. This
nose tire load may not exceed 1.5 times
the load rating of the tire.
(c) When a landing gear axle is fitted
with more than one wheel and tire assembly, such as dual or dual-tandem,
each wheel must be fitted with a suitable tire of proper fit with a speed rating approved by the Administrator
that is not exceeded under critical conditions, and with a load rating approved by the Administrator that is
not exceeded by - 
(1) The loads on each main wheel
tire, corresponding to the most critical
combination of airplane weight (up to
maximum weight) and center of gravity position, when multiplied by a factor of 1.07; and
(2) Loads specified in paragraphs
(a)(2), (b)(1), (b)(2), and (b)(3) of this
section on each nose wheel tire.
(d) Each tire installed on a retractable landing gear system must, at the
maximum size of the tire type expected
in service, have a clearance to surrounding structure and systems that is
adequate to prevent unintended contact between the tire and any part of
the structure or systems.
(e) For an airplane with a maximum
certificated takeoff weight of more
than 75,000 pounds, tires mounted on
braked wheels must be inflated with
dry nitrogen or other gases shown to be
inert so that the gas mixture in the
tire does not contain oxygen in excess
of 5 percent by volume, unless it can be

shown that the tire liner material will
not produce a volatile gas when heated
or that means are provided to prevent
tire temperatures from reaching unsafe
levels.
[Amdt. 25-48, 44 FR 68752, Nov. 29, 1979; Amdt.
25-72, 55 FR 29777, July 20, 1990, as amended
by Amdt. 25-78, 58 FR 11781, Feb. 26, 1993]

Section 25.735

Brakes and braking systems.

(a) Approval. Each assembly consisting of a wheel(s) and brake(s) must
be approved.
(b) Brake system capability. The brake
system, associated systems and components must be designed and constructed so that:
(1) If any electrical, pneumatic, hydraulic, or mechanical connecting or
transmitting element fails, or if any
single source of hydraulic or other
brake operating energy supply is lost,
it is possible to bring the airplane to
rest with a braked roll stopping distance of not more than two times that
obtained in determining the landing
distance as prescribed in Section 25.125.
(2) Fluid lost from a brake hydraulic
system following a failure in, or in the
vicinity of, the brakes is insufficient to
cause or support a hazardous fire on
the ground or in flight.
(c) Brake controls. The brake controls
must be designed and constructed so
that:
(1) Excessive control force is not required for their operation.
(2) If an automatic braking system is
installed, means are provided to:
(i) Arm and disarm the system, and
(ii) Allow the pilot(s) to override the
system by use of manual braking.
(d) Parking brake. The airplane must
have a parking brake control that,
when selected on, will, without further
attention, prevent the airplane from
rolling on a dry and level paved runway
when the most adverse combination of
maximum thrust on one engine and up
to maximum ground idle thrust on any,
or all, other engine(s) is applied. The
control must be suitably located or be
adequately protected to prevent inadvertent operation. There must be indication in the cockpit when the parking
brake is not fully released.
(e) Antiskid system. If an antiskid system is installed:

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